I've been playing with all sorts of social web sites. Ostensibly, it's because I'm interested in the technology (OpenID, RSS, FOAF, hCard, XFN, etc.)... but to be honest they're just kinda nifty. :p
Here are a few profile links:
Twitter:
http://twitter.com/silvermoon82Lifestrea.ms:
http://lifestrea.ms/user/silvermoon82 - this one is extremely nifty: among other things, it integrates very well into lots of other services, so:
* when you post a link to Lifestrea.ms, it can also be posted to your Del.icio.us account and Twitter,
* Status updates can be sent on to Facebook, Twitter, &c.
- They are also hardcore into open standards and sharing formats - RSS everything, hCard & XFN, OpenID, all the neat web interop technologies I've been getting interested in.
Lifesrea.ms is in private beta right now; if you're interested in trying it out, send me a message and I'll give you an invite (remember the early days of Gmail? Bonus is that there doesn't seem to be any limit on number of invites).