Google's announcement that they will be processing RDFa found whilst indexing our web-pages certainly got many people all of a Twitter last week. Many useful posts have examined the effect that this will have on search, especially when combined with Yahoo!'s already existing efforts in this direction (they began processing RDFa about a year ago).
Some commentators also point to the effect this could have on the semantic web, accelerating uptake (although as is often the case with semantic web enthusiasts, ground-breaking initiatives that could change the web as we know it, are never quite good enough).
This post isn't about either of those things though. It's about a point that hasn't yet been raised, but will have equally far-reaching effects, and that is the role that processing RDFa will have on how we manage our personal data.
Who owns your data?
Publishing to the web has never been easier. With the proliferation of content management systems, online blogging platforms, microblogging, and more, just about anyone from individuals to small businesses, from clubs to multinational organisations can become a part of the web.
However, whilst publishing one page or a thousand is now straightforward, publishing data is generally the preserve of organisations prepared to manage their own IT.
To a large extent this has changed in the recent period, as individuals have signed up for web 2.0 services that will store their data for them, as well as providing slick user interfaces with which to manage that data.
But there's a contradiction here, that we can't imagine being sustained forever; the value of most web 2.0 services comes from the enormous quantity of data that they are 'borrowing' from their members. And further, a significant part of that value comes from the inertia created by the difficulty of moving your data from one service to another.
Yet if it was possible to control and publish your own data, on your own site, and then simply point third-party services to your information, then moving from one service to another would be as easy as signing up to a new service.
RDFa makes this possible, because RDFa provides a straightforward means by which any data can be published as easily as a web-page.
From large organisations to the individual blogger, anyone can now publish data by simply placing extra markup in their pages.
And that puts individuals back in control of their own data.
(For some ideas on how you might manage your data, and related themes, take a look at Steven Pemberton's lively presentation, [Why you should have a web- site (and other Web 3.0 issues)](http://www.w3.org/2009/Talks/01-15-steven- website/).)
After web 2.0
So instead of burying our data in an ever-growing array of online services, we will simply publish once, and allow third-party services to consume our information. Whether it's our individual profile or items we have for sale, whether it's a review we wrote of a restaurant or film, or some of our favourite recipes, our web-pages will become our own, personal API.
By making it possible for everyone to have an API, RDFa creates the possibility of a new generation of applications that will operate across our data.
(For some thoughts on the API idea as it might apply to corporate and government data, see Jeni Tennison's Your Website is Your API: Quick Wins for Government Data.)
This isn't something that will happen overnight. But it does mean that any service that is founded on trying to 'own' a user's data, when in fact they have merely 'borrowed' it, will need to look long and hard at how RDFa is set to change the landscape.