It depends upon the interest of the user, Today Facebook, LinkedIn and twitter are the most visted social networking sites.
Well... different.
I like Twitter for it's simplicity.
I like LinkedIn for professional opportunities and interesting people that i've meet there.
I like Google+ because sooner or later it will affect the SEO process.
I also like Identi.ca and Sharetronix for their path (they're both open source and can be tweaked for many purposes)
Facebook is something casual these days. If you remember old times when social network was MySpace then you should remember how Facebook was something "different". But times has changed and we're too!
Social networking site would your like the most
facebook ,twitter,fliker.com
Facebook, Google plus, Linkedin, and Twitter
Facebook, Google plus, Linkedin, and Twitter
Facebook, Twitter, StumbleUpon, Delicious etc
It's depends on taste and convenience and other factors.
To attracts a lot of potential customers Facebook.
To attracts a lot of customers through Images Pinterest
To increase B2B Linkedin.
Increase followers Twitters.
Personally convenience Facebook.
To increase SEO rankings and share to groups Google plus....
Definitely Facebook and Twitter.
Twitter, LinkedIn.
Facebook!
give name
Twitter and Quora
I love to use Facebook and Twitter :)