Not sure if anyone posted this but... Facebook Posts Are 3 Times More Powerful Than Tweets
"For shares and Tweets, we were able to directly attribute sales to the original action, so we simply took the total revenue attributed to each action and divided it by the total number of shares/tweets. For likes and follows, we had to estimate attribution by looking at our traffic references and subtracting out purchases made through shares/tweets as well as purchases made through direct traffic. None of our analysis captures long-term value of customers acquired through these social channels – which means the true value per action should be even greater. Gross revenue depends on the products/services being sold."
Social media marketing is about branding, and through branding you spread the word of who you are and what you do. Facebook will rarely be the "source" of where your customer came from, but it maybe where they originated from. Their sister follows you and see you have a tent sale going on and tells her brother who tells his gf and she comes in and purchases a car. The best you can do to measure this as earlier mentioned is ask every customer who comes in if they follow you on facebook, twitter, merchantcirlce, foursqaure, plurk, etc. But these should be to bring awareness and brand yourself.
If you really want your customers to be involved and actually listen to the shares/tweet/etc you post then you have to make sure to be diverse. Don't just post status updates about "this Monday huge sale" "this Tuesday free oil change" you want to be interactive and talk about what your audience is interested in, share positive quotes, recipes, etc.
