said 5 months, 1 week ago:
It depends on what type of analytics you want to see.
If you want to see what social traffic is coming to your site and how it potentially leads to conversions then Google analytics is the way to go (Kristi’s link explains this perfectly).
If you just want visibility of where and who is sharing your links then topsy.com is a nice free tool that gives you results back from Twitter and Google plus.
Socialmention.com is another to try, this does pull in information from blogs, comments and various other places.