Social Media is all the rage right now. The advertising mediums are ever-changing and Facebook is leading the charge, along with Twitter.  I believe Social Media has its place in a businesses online marketing initiatives.  However, the ROI must be measurable. Until recently conversion codes were not available in Facebook.  now they are.  here is a link to a page detailing everything you would ever want to know about Facebook conversion codes.

http://www.facebook.com/help/?page=994