Delicious, Digg, Reddit, Facebook, StumbleUpon, Twitter, LinkedIn, MySpace and many more but make more friends and followers.

Google+,Facebook, Twitter,

Delicious, reddit, digg, facebook, pinterest, twitter, Linkedin is the best social network for SEO.

Facebook, Twitter and Instagram is the best social networking sites.

Social networking sites are really very good for getting traffic I mostly use following social networking sites:
Facebook,
Google plus,
Twitter,
My space,
Kiwibox,
hi5,
Etc.....

social media can earn you better rankings. Even if you are sceptical of the correlation that the social shares directly improved the rankings there’s also the factor that getting more people to see the content also lead to more links and visibility

Facebook and twitter

Mostly Facebook, Twitter, Google+, Pinterest and LinkedIn are the best social media sites for website promotion.

Social media sites a key part of your SEO strategy. Importance of social networks