Get all the big cats of the web such as Google, Microsoft, Apple, Twitter and Yahoo in one room and they will argue about a lot of things. But they all agree that "HTML5 is the future of the web".
So it matters to those of us in the Semantic Web community that RDFa gets included in HTML5. There has been a lot of debate about this at a technical level. This post from Jeni's Musings is a good introduction to the debate.
The question is whether the recent momentum behind RDFa, such as Facebook's adoption for their Open Graph protocol and the inclusion within Drupal 7, will lead to adoption within HTML5.
Does It Matter & When? We Ask Manu Sporny
We asked Manu Sporny. He knows a thing or two about RDFa:
Manu Sporny is the Founder and CEO of Digital Bazaar, Inc. He is also the Co-Chair of the RDFa Working Group at the World Wide Web Consortium. His background is in Computer Science, focusing on advancing the state of the art on the Web, micro-payment mechanisms, peer-to-peer networks and creating fair systems that compensate individuals for their creative efforts. He is also the leader of the PaySwarm movement - an open standard for copyright-aware, legal peer-to-peer networks for distributing music, movies and books.
We asked Manu two questions:
Does It Matter That RDFa Gets Into HTML5 Spec?
"The short answer is no, RDFa will continue to be successful regardless
of which specification refers to it. RDFa has been successful because it is a solid technology that provides real value for those that use it, not because it is in a certain specification.
Ultimately, whether a W3C technology is successful or not is entirely
dependent on the people and companies that implement it. In that regard, RDFa is a wildly successful W3C technology.
The primary confusion about RDFa in HTML5 revolves around there being
two HTML5 documents - the WHAT WG version of HTML5 and the HTML WG (W3C) version of HTML5. The WHAT WG version is controlled by a tight group and decisions are made primarily by the editor of that specification. The HTML WG version is developed and maintained by consensus and so enjoys a broader range of opinions on what should and shouldn't be in HTML5.
A number of individuals in the WHAT WG community had rejected the
inclusion of RDFa in 2009 and invented their own mechanism, which has
been met with much less enthusiasm than RDFa. So, while the WHAT WG
HTML5 spec doesn't include RDFa, the specifications related to HTML5
published via the HTML WG (W3C) do include RDFa.
The WHAT WG will not be able to ignore the reality of RDFa adoption for
much longer. They have a good track record of reflecting reality in
their HTML5 document - they'll come around.
Even if they don't, the W3C is publishing an HTML5+RDFa spec. If the W3C doesn't follow through on the final HTML5+RDFa spec, there will still be a spec somewhere. RDFa Processors will still consume RDFa from HTML5 documents, just as they do today.
This genie isn't going back in the bottle."
Will RDFa Gets Into HTML5 Spec? When?
"RDFa is already a part of HTML5 at the W3C - this happened when the First Public Working Draft for HTML+RDFa was approved in late 2009.
There is quite a bit of history here, but focusing purely on just the
documents, RDFa is a layered specification. That means that there is a
base specification (called RDFa Core 1.1) and a language-specific implementation, also known as a "thin" specification that layers on top of RDFa Core 1.1. XHTML+RDFa is a good example of such a "thin" specification. The way RDFa is integrated into HTML5 is through this mechanism, a "thin" specification.
The next HTML5+RDFa thin specification will be ready to be published at
some point in May 2010 and will incorporate all of the new RDFa 1.1
features (which were published earlier this month).
The HTML Working Group intends to pursue RDFa in HTML5 (aka: HTML+RDFa)
until it is an official W3C Recommendation (that is, until it is an
That doesn't mean that it is guaranteed to make it. It does mean that as long as things don't go horribly wrong, we plan to make it an official specification. Member companies at the W3C could still decide to vote against HTML+RDFa. We don't expect that to happen, especially since it has received massive deployment support: Yahoo, Google, Facebook, Drupal7, BBC, Tesco, SVG, Open Document Format, O'Reilly Publishing, Rotten Tomatoes, Digg, The Public Library of Science, to name just a few.
You don't have to wait until the HTML5 specification is done to use RDFa today. You can use XHTML+RDFa 1.0 which became an official W3C specification back in 2009. We expect XHTML+RDFa 1.1 to become an official specification some time in 2011. RDFa 1.1 is primarily aimed at making authoring of RDFa easier for web page authors."