Microdata Problem Descriptions
Exposing known data types in a reusable way
USE CASE: Exposing calendar events so that users can add those events to their calendaring systems.
- A user visits the Avenue Q site and wants to make a note of when tickets go on sale for the tour's stop in his home town. The site says "October 3rd", so the user clicks this and selects "add to calendar", which causes an entry to be added to his calendar.
- A student is making a timeline of important events in Apple's history. As he reads Wikipedia entries on the topic, he clicks on dates and selects "add to timeline", which causes an entry to be added to his timeline.
- TV guide listings - browsers should be able to expose to the user's tools (e.g. calendar, DVR, TV tuner) the times that a TV show is on.
- Paul sometimes gives talks on various topics, and announces them on his blog. He would like to mark up these announcements with proper scheduling information, so that his readers' software can automatically obtain the scheduling information and add it to their calendar. Importantly, some of the rendered data might be more informal than the machine-readable data required to produce a calendar event. Also of importance: Paul may want to annotate his event with a combination of existing vocabularies and a new vocabulary of his own design. (why?)
- David can use the data in a web page to generate a custom browser UI for adding an event to our calendaring software without using brittle screen-scraping.
- Should be discoverable.
- Should be compatible with existing calendar systems.
- Should be unlikely to get out of sync with prose on the page.
- Shouldn't require the consumer to write XSLT or server-side code to read the calendar information.
- Machine-readable event data shouldn't be on a separate page than human-readable dates.
- The information should be convertible into a dedicated form (RDF, JSON, XML, iCalendar) in a consistent manner, so that tools that use this information separate from the pages on which it is found have a standard way of conveying the information.
- Should be possible for different parts of an event to be given in different parts of the page. For example, a page with calendar events in columns (with each row giving the time, date, place, etc) should still have unambiguous calendar events parseable from it.
USE CASE: Exposing contact details so that users can add people to their address books or social networking sites.
- Instead of giving a colleague a business card, someone gives their colleague a URL, and that colleague's user agent extracts basic profile information such as the person's name along with references to other people that person knows and adds the information into an address book.
- A scholar and teacher wants other scholars (and potentially students) to be able to easily extract information about who he is to add it to their contact databases.
- Fred copies the names of one of his Facebook friends and pastes it into his OS address book; the contact information is imported automatically.
- Fred copies the names of one of his Facebook friends and pastes it into his Webmail's address book feature; the contact information is imported automatically.
- David can use the data in a web page to generate a custom browser UI for including a person in our address book without using brittle screen-scraping.
- A user joining a new social network should be able to identify himself to the new social network in way that enables the new social network to bootstrap his account from existing published data (e.g. from another social nework) rather than having to re-enter it, without the new site having to coordinate (or know about) the pre-existing site, without the user having to give either sites credentials to the other, and without the new site finding out about relationships that the user has intentionally kept secret. (http://w2spconf.com/2008/papers/s3p2.pdf)
- Data should not need to be duplicated between machine-readable and human-readable forms (i.e. the human-readable form should be machine-readable).
- Shouldn't require the consumer to write XSLT or server-side code to read the contact information.
- Machine-readable contact information shouldn't be on a separate page than human-readable contact information.
- The information should be convertible into a dedicated form (RDF, JSON, XML, vCard) in a consistent manner, so that tools that use this information separate from the pages on which it is found have a standard way of conveying the information.
- Should be possible for different parts of a contact to be given in different parts of the page. For example, a page with contact details for people in columns (with each row giving the name, telephone number, etc) should still have unambiguous grouped contact details parseable from it.
USE CASE: Allow users to maintain bibliographies or otherwise keep track of sources of quotes or references.
- Frank copies a sentence from Wikipedia and pastes it in some word processor: it would be great if the word processor offered to automatically create a bibliographic entry.
- Patrick keeps a list of his scientific publications on his web site. He would like to provide structure within this publications page so that Frank can automatically extract this information and use it to cite Patrick's papers without having to transcribe the bibliographic information.
- A scholar and teacher wants other scholars (and potentially students) to be able to easily extract information about what he has published to add it to their bibliographic applications.
- A scholar and teacher wants to publish scholarly documents or content that includes extensive citations that readers can then automatically extract so that they can find them in their local university library. These citations may be for a wide range of different sources: an interview posted on YouTube, a legal opinion posted on the Supreme Court web site, a press release from the White House.
- A blog, say htmlfive.net, copies content wholesale from another, say blog.whatwg.org (as permitted and encouraged by the license). The author of the original content would like the reader of the reproduced content to know the provenance of the content. The reader would like to find the original blog post so he can leave comments for the original author.
- Chaals could improve the Opera intranet if he had a mechanism for identifying the original source of various parts of a page, as that would let him contact the original author quickly to report problems or request changes.
- Machine-readable bibliographic information shouldn't be on a separate page than human-readable bibliographic information.
- The information should be convertible into a dedicated form (RDF, JSON, XML, BibTex) in a consistent manner, so that tools that use this information separate from the pages on which it is found have a standard way of conveying the information.
USE CASE: Help people searching for content to find content covered by licenses that suit their needs.
- If a user is looking for recipes of pies to reproduce on his blog, he might want to exclude from his results any recipes that are not available under a license allowing non-commercial reproduction.
- Lucy wants to publish her papers online. She includes an abstract of each one in a page, but because they are under different copyright rules, she needs to clarify what the rules are. A harvester such as the Open Access project can actually collect and index some of them with no problem, but may not be allowed to index others. Meanwhile, a human finds it more useful to see the abstracts on a page than have to guess from a bunch of titles whether to look at each abstract.
- There are mapping organisations and data producers and people who take photos, and each may place different policies. Being able to keep that policy information helps people with further mashups avoiding violating a policy. For example, if GreatMaps.com has a public domain policy on their maps, CoolFotos.org has a policy that you can use data other than images for non-commercial purposes, and Johan Ichikawa has a photo there of my brother's café, which he has licensed as "must pay money", then it would be reasonable for me to copy the map and put it in a brochure for the café, but not to copy the data and photo from CoolFotos. On the other hand, if I am producing a non-commercial guide to cafés in Melbourne, I can add the map and the location of the cafe photo, but not the photo itself.
- Tara runs a video sharing web site for people who want licensing information to be included with their videos. When Paul wants to blog about a video, he can paste a fragment of HTML provided by Tara directly into his blog. The video is then available inline in his blog, along with any licensing information about the video.
- Fred's browser can tell him what license a particular video on a site he is reading has been released under, and advise him on what the associated permissions and restrictions are (can he redistribute this work for commercial purposes, can he distribute a modified version of this work, how should he assign credit to the original author, what jurisdiction the license assumes, whether the license allows the work to be embedded into a work that uses content under various other licenses, etc).
- Flickr has images that are CC-licensed, but the pages themselves are not.
- Blogs may wish to reuse CC-licensed images without licensing the whole blog as CC, but while still including attribution and license information (which may be required by the licenses in question).
- Content on a page might be covered by a different license than other content on the same page.
- When licensing a subpart of the page, existing implementations must not just assume that the license applies to the whole page rather than just part of it.
- License proliferation should be discouraged.
- License information should be able to survive from one site to another as the data is transfered.
- Expressing copyright licensing terms should be easy for content creators, publishers, and redistributors to provide.
- It should be more convenient for the users (and tools) to find and evaluate copyright statements and licenses than it is today.
- Shouldn't require the consumer to write XSLT or server-side code to process the license information.
- Machine-readable licensing information shouldn't be on a separate page than human-readable licensing information.
- There should not be ambiguous legal implications.
USE CASE: Annotate structured data that HTML has no semantics for, and which nobody has annotated before, and may never again, for private use or use in a small self-contained community.
- A group of users want to mark up their iguana collections so that they can write a script that collates all their collections and presents them in a uniform fashion.
- A scholar and teacher wants other scholars (and potentially students) to be able to easily extract information about what he teaches to add it to their custom applications.
- The list of specifications produced by W3C, for example, and various lists of translations, are produced by scraping source pages and outputting the result. This is brittle. It would be easier if the data was unambiguously obtainable from the source pages. This is a custom set of properties, specific to this community.
- Chaals wants to make a list of the people who have translated W3C specifications or other documents, and then use this to search for people who are familiar with a given technology at least at some level, and happen to speak one or more languages of interest.
- Chaals wants to have a reputation manager that can determine which of the many emails sent to the WHATWG list might be "more than usually valuable", and would like to seed this reputation manager from information gathered from the same source as the scraper that generates the W3C's TR/ page.
- A user wants to write a script that finds the price of a book from an Amazon page.
- Todd sells an HTML-based content management system, where all documents are processed and edited as HTML, sent from one editor to another, and eventually published and indexed. He would like to build up the editorial metadata used by the system within the HTML documents themselves, so that it is easier to manage and less likely to be lost.
- Tim wants to make a knowledge base seeded from statements made in Spanish and English, e.g. from people writing down their thoughts about George W. Bush and George H.W. Bush, and has either convinced the people making the statements that they should use a common language-neutral machine-readable vocabulary to describe their thoughts, or has convinced some other people to come in after them and process the thoughts manually to get them into a computer-readable form.
- Vocabularies can be developed in a manner that won't clash with future more widely-used vocabularies, so that those future vocabularies can later be used in a page making use of private vocabularies without making the earlier annotations ambiguous.
- Using the data should not involve learning a plethora of new APIs, formats, or vocabularies (today it is possible, e.g., to get the price of an Amazon product, but it requires learning a new API; similarly it's possible to get information from sites consistently using 'class' values in a documented way, but doing so requires learning a new vocabulary).
- Shouldn't require the consumer to write XSLT or server-side code to process the annotated data.
- Machine-readable annotations shouldn't be on a separate page than human-readable annotations.
- The information should be convertible into a dedicated form (RDF, JSON, XML) in a consistent manner, so that tools that use this information separate from the pages on which it is found have a standard way of conveying the information.
- Should be possible for different parts of an item's data to be given in different parts of the page, for example two items described in the same paragraph. ("The two lamps and A and B. The first is $20, the second $30. The first is 5W, the second 7W.")
- It should be possible to define globally-unique names, but the syntax should be optimised for a set of predefined vocabularies.
- Adding this data to a page should be easy.
- The syntax for adding this data should encourage the data to remain accurate when the page is changed.
- The syntax should be resilient to intentional copy-and-paste authoring: people copying data into the page from a page that already has data should not have to know about any declarations far from the data.
- The syntax should be resilient to unintentional copy-and-paste authoring: people copying markup from the page who do not know about these features should not inadvertently mark up their page with inapplicable data.
- Any additional markup or data used to allow the machine to understand the actual information shouldn't be redundantly repeated (e.g. on each cell of a table, when setting it on the column is possible).
Validation of Expressed Micro-data
USE CASE: It should be possible to write generalized validators and authoring tools for the annotations described in the previous use case.
- Mary would like to write a generalized software tool to help page authors express micro-data. One of the features that she would like to include is one that displays authoring information, such as vocabulary term description, type information, range information, and other vocabulary term attributes in-line so that authors have a better understanding of the vocabularies that they're using.
- John would like to ensure that his indexing software only stores type-valid data. Part of the mechanism that he uses to check the incoming micro-data stream is type information that is embedded in the vocabularies that he uses.
- Steve, would like to provide warnings to the authors that use his vocabulary that certain vocabulary terms are experimental and may never become stable.
- There should be a definitive location for vocabularies.
- It should be possible for vocabularies to describe other vocabularies.
- Originating vocabulary documents should be discoverable.
- Machine-readable vocabulary information shouldn't be on a separate page than the human-readable explanation.
- There must not be restrictions on the possible ways vocabularies can be expressed (e.g. the way DTDs restricted possible grammars in SGML).
USE CASE: Allow authors to annotate their documents to highlight the key parts, e.g. as when a student highlights parts of a printed page, but in a hypertext-aware fashion.
- Fred writes a page about Napoleon. He can highlight the word Napoleon in a way that indicates to the reader that that is a person. Fred can also annotate the page to indicate that Napoleon and France are related concepts.
USE CASE: Site owners want a way to provide enhanced search results to the engines, so that an entry in the search results page is more than just a bare link and snippet of text, and provides additional resources for users straight on the search page without them having to click into the page and discover those resources themselves.
- For example, in response to a query for a restaurant, a search engine might want to have the result from yelp.com provide additional information, e.g. info on price, rating, and phone number, along with links to reviews or photos of the restaurant.
- Information for the search engine should be on the same page as information that would be shown to the user if the user visited the page.
USE CASE: Search engines and other site categorisation and aggregation engines should be able to determine the contents of pages with more accuracy than today.
- Students and teachers should be able to discover each other -- both within an institution and across institutions -- via their blogging.
- A blogger wishes to categorise his posts such that he can see them in the context of other posts on the same topic, including posts by unrelated authors (i.e. not via a pre-agreed tag or identifier, not via a single dedicated and preconfigured aggregator).
- A user whose grandfather is called "Napoleon" wishes to ask Google the question "Who is Napoleon", and get as his answer a page describing his grandfather.
- A user wants to ask about "Napoleon" but, instead of getting an answer, wants the search engine to ask him which Napoleon he wants to know about.
- Should not disadvantage pages that are more useful to the user but that have not made any effort to help the search engine.
- Should not be more susceptible to spamming than today's markup.
USE CASE: Web browsers should be able to help users find information related to the items discussed by the page that they are looking at.
- Finding more information about a movie when looking at a page about the movie, when the page contains detailed data about the movie.
- For example, where the movie is playing locally.
- For example, what your friends thought of it.
- Exposing music samples on a page so that a user can listen to all the samples.
- David can use the data in a web page to generate a custom browser UI for calling a phone number using our cellphone without using brittle screen-scraping.
- Should be discoverable, because otherwise users will not use it, and thus users won't be helped.
- Should be consistently available, because if it only works on some pages, users will not use it (see, for instance, the rel=next story).
- Should be bootstrapable (rel=next failed because UAs didn't expose it because authors didn't use it because UAs didn't expose it).
USE CASE: Finding distributed comments on audio and video media.
- Sam has posted a video tutorial on how to grow tomatoes on his video blog. Jane uses the tutorial and would like to leave feedback to others that view the video regarding certain parts of the video she found most helpful. Since Sam has comments disabled on his blog, his users cannot comment on the particular sections of the video other than linking to it from their blog and entering the information there. Jane uses a video player that aggregates all the comments about the video found on the Web, and displays them as subtitles while she watches the video.
- It shouldn't be possible for Jane to be exposed to spam comments.
- The comment-aggregating video player shouldn't need to crawl the entire Web for each user independently.
USE CASE: Allow users to price-check digital media (music, TV shows, etc) and purchase such content without having to go through a special website or application to acquire it, and without particular retailers being selected by the content's producer or publisher.
- Joe wants to sell his music, but he doesn't want to sell it through a specific retailer, he wants to allow the user to pick a retailer. So he forgoes the chance of an affiliate fee, negotiates to have his music available in all retail stores that his users might prefer, and then puts a generic link on his page that identifies the product but doesn't identifier a retailer. Kyle, a fan, visits his page, clicks the link, and Amazon charges his credit card and puts the music into his Amazon album downloader. Leo instead clicks on the link and is automatically charged by Apple, and finds later that the music is in his iTunes library.
- Manu wants to go to Joe's website but check the price of the offered music against the various retailers that sell it, without going to those retailers' sites, so that he can pick the cheapest retailer.
- David can use the data in a web page to generate a custom browser UI for buying a song from our favorite online music store without using brittle screen-scraping.
- Should not be easily prone to clickjacking (sites shouldn't be able to charge the user without the user's consent).
- Should not make transactions harder when the user hasn't yet picked a favourite retailer.
USE CASE: Allow the user to perform vertical searches across multiple sites even when the sites don't include the information the user wants.
- Kjetil is searching for new hardware for his desktop and most of the specs he does not care about too much, but he's decided that he wants a 45 nm CPU with at least a 1333 MHz FSB and at least 2800 MHz clock frequency, and a thermal energy of at most 65 W. The motherboard needs to have at least 2 PCI ports, unless it has an onboard Wifi card, and it needs to accommodate for at least 12 GB of DDR3 RAM, which needs to match the FSB frequency. Furthermore, all components should be well supported by Linux and the RAID controller should have at least RAID acceleration. None of the manufacturer sites have information about the RAID controllers, that information is only available form various forums.
- Fred is going to buy a property. The property needs to be close to the forest, yet close to a train station that will take him to town in less than half an hour. It needs to have a stable snow-fall in the winter, and access to tracks that are regularly prepared for XC skating. The property should be of a certain size, and proximity to kindergarten and schools. It needs to have been regulated for residential use and have roads and the usual infrastructure. Furthermore, it needs to be on soil that is suitable for geothermal heating yet have a low abundance of uranium. It should have a good view of the fjord to the southeast.
- Performing search searches should be feasible and cheap.
- It should be possible to perform such searches without relying on a third-party to seek out the information.
- The tool that collects information must not require the information to be marked up in some special way, since manufacturers don't include all the information, and users on forums (where the information can sometimes be found) are unlikely to mark it up in some particularly machine-readable way.
USE CASE: Copy-and-paste should work between Web apps and native apps and between Web apps and other Web apps.
- Fred copies an e-mail from Apple Mail into GMail, and the e-mail survives intact, including headers, attachments, and multipart/related parts.
- Fred copies an e-mail from GMail into Hotmail, and the e-mail survives intact, including headers, attachments, and multipart/related parts.
USE CASE: Allow users to share data between sites (e.g. between an online store and a price comparison site).
- Lucy is looking for a new apartment and some items with which to furnish it. She browses various web pages, including apartment listings, furniture stores, kitchen appliances, etc. Every time she finds an item she likes, she points to it and transfers its details to her apartment-hunting page, where her picks can be organized, sorted, and categorized.
- Lucy uses a website called TheBigMove.com to organize all aspects of her move, including items that she is tracking for the move. She goes to her "To Do" list and adds some of the items she collected during her visits to various Web sites, so that TheBigMove.com can handle the purchasing and delivery for her.
- Should be discoverable, because otherwise users will not use it, and thus users won't be helped.
USE CASE: Remove the need for feeds to restate the content of HTML pages (i.e. replace Atom with HTML).
- Paul maintains a blog and wishes to write his blog in such a way that tools can pick up his blog post tags, authors, titles, and his blogroll directly from his blog, so that he does not need to maintain a parallel version of his data in a "structured format." In other words, his HTML blog should be usable as its own structured feed.
USE CASE: Allow users to compare subjects of blog entries when the subjects are hard to tersely identify relative to other subjects in the same general area.
- Paul blogs about proteins and genes. His colleagues also blog about proteins and genes. Proteins and genes are identified by long hard-to-compare strings, but Paul and his colleagues can determine if they are talking about the same things by having their user agent compare some sort of flags embedded in the blogs.
- Rob wants to publish a large vocabulary in RDFS and/or OWL. Rob also wants to provide a clear, human readable description of the same vocabulary, that mixes the terms with descriptive text in HTML.
USE CASE: Allow blogs to be aggregated along subject lines.
- At University of Mary Washington, many faculty encourage students to blog about their studies to encourage more discussion using an instance of WordPress MultiUser. A student with have a blog might be writing posts relevant to more than one class. Professors would like to then aggregate relevant posts into one blog.
Data extraction from sites without explicit cooperation from those sources
USE CASE: Getting data out of poorly written Web pages, so that the user can find more information about the page's contents.
- Alfred merges data from various sources in a static manner, generating a new set of data. Bob later uses this static data in conjunction with other data sets to generate yet another set of static data. Julie then visits Bob's page later, and wants to know where and when the various sources of data Bob used come from, so that she can evaluate its quality. (In this instance, Alfred and Bob are assumed to be uncooperative, since creating a static mashup would be an example of a poorly-written page.)
- TV guide listings - If the TV guide provider does not render a link to IMDB, the browser should recognise TV shows and give implicit links. (In this instance, it is assumed that the TV guide provider is uncooperative, since it isn't providing the links the user wants.)
- Students and teachers should be able to discover each other -- both within an institution and across institutions -- via their blogging. (In this instance, it is assumed that the teachers and students aren't cooperative, since they would otherwise be able to find each other by listing their blogs in a common directory.)
- Tim wants to make a knowledge base seeded from statements made in Spanish and English, e.g. from people writing down their thoughts about George W. Bush and George H.W. Bush. (In this instance, it is assumed that the people writing the statements aren't cooperative, since if they were they could just add the data straight into the knowledge base.)
- Does not need cooperation of the author (if the page author was cooperative, the page would be well-written).
- Shouldn't require the consumer to write XSLT or server-side code to derive this information from the page.
USE CASE: Remove the need for RDF users to restate information in online encyclopedias (i.e. replace DBpedia).
- A user wants to have information in RDF form. The user visits Wikipedia, and his user agent can obtain the information without relying on DBpedia's interpretation of the page.
- All the data exposed by DBpedia should be derivable from Wikipedia without using DBpedia.