[thinkingisfun]

Especially since it's already been done: http://friendica.com/

^ And that is hardly the only project, and it could use improvements like everything, but it's one that surprised me when I first heard of it, because it really does a lot and, well, nobody ever mentions it..!

One link of note, not that much there yet but surely something I will watch eagerly: http://www.w3.org/community/fedsocweb/

If you wanna do it right, do it right.