2008 is the Year To Share DataFacebook announced today they are joining the Dataportability Workgroup This unexpected move could help accelerate acceptance from other large social websites. APML is another data sharing protocol that is gaining some momentum. Essentially it is an attempt to define a common set of standards to allow personal Attention Profile data (bookmarks, photos, blog posts, browsing history, music interests, etc) to be transported (painlessly) to other web services and applications.
For instance you could group together items for public consumption separately from those for specific private groups and publish appropriate access for each, even though the items themselves are located in different places.
Now if only we could resolve all the issues surrounding data privacy.