XFN and FOAF were two small steps in that direction, and Google just built on them with the Social Graph API (watch the friendly little video intro).
Any day now we’ll see an application that not only helps us generate XFN and FOAF data, but does so in a way that manages our online identities, particularly with regards to search. It’ll tip the balance of art and science in SEO toward science.
Top-down semantic web visions were judged by skeptical-but-realistic critics to be overly systematic. Well, yes, but if we get there a piece at a time, helping people understand, implement, experiment, and capitalize with each little piece, we’ll get there in an organic way.
Time to go generate some XFN…