I have made sales from social media but I wouldnīt ever advise a client of mine to go full steam ahead with social media but I would advise they stick their foot in a little but focus on other areas while running social media alongside their marketing
Twitter is where I have made sales mainly but also from Facebook groups
I find that Social Media is a great way of getting your brand name out there but very few sales are generated from it - unless you are Dell - LOL (who have now made in excess of $2 million just from Twitter sales alone!)
I am on the majority of the social media websites (although I have just been thrown off Facebook - how stylish! According to them I have been reported for abuse - but I am never in the habit of abusing anyone, falsely accused without a doubt there) such as MySpace, Facebook, Linkedin, Bebo, Twitter and the list goes on
I donīt know the stats with regards to sales vs social media but I would hazard a guess the stats are not as bright as sales vs Google.
I also run a Scoliosis support group and via Twitter I have gained more members but I am not selling anything with that, just pure and simple support, therefore making it easier to network with people