Social Networking alternatives

I've been using twitter for 2 purposes, it gets my links indexed, and it brings in some direct traffic. However just recently twittter has starting getting picky about my accounts, and is suspending far to many. I'm experiement to try and improve my tweeter life, but in the meantime, what other sites offer similar benefits, inparticular direct traffic, as I believe most sites will in someway help with indexing.

Thanks

Tumblr is perhaps the best alternative to Twitter, solving many issues that the social messaging giant suffers from including the 140 character max message limit.