I use Twitter, Facebook and Linkedin and get a good deal of business and meet tons of awesome people from it.
Other General Social Network
Niche Social Networks
I Only use Twitter
I don't use social networks
I use over 10 different Social Networks
Twitter and Digg are by far the most valuable of the social networks listed in terms of seo.
Yahoo meme is a twitter clone that I don't think will take off. Bing and Google are giving twitter to much juice.
why is meme not listed? yahoo meme is getting getting crowded too
apart fro twitter, tagged is good and meme is also good looking and drives traffic....
I use facebook, twitter, digg and orkut.
I use facebook and twitter. These sites are the best.