To properly leverage social media sites I recommend that most businesses, learn as much as they can from experts before wasting countless hours trying to leverage facebook / twitter... While this activity is useful, we first need to examine some basic things first.
What do they do? How old are they? What kind of car do they drive? We have our clients answer this question along with others before we suggest any social networking work.
With the combination of knowing how much a customer is worth, and with website analytics installed, we can then tell you how much a visitor to your site is worth to your business.