Facebook

Hi, I have a store where i sell products. I already have functionality at my store where people can share products to their facebook feed. What I am looking for is a way to track when other users share that same product from their facebook page and so on. I want to track the different users down a number of tiers. Like if John shared a product from our store at his fb page and then his friend Simon shared that product (John > Simon) then i want to be able to capture Simons information (name and email address) and store that in my database.  I want to track down many levels. My website will plot the tiers i just need to know user info (name and email address) of anybody who shared the product that John originally shared. I need someone who has experience in developing for facebook. I will also want to see some examples of your work. Thanks Desired Skills Facebook Development, PHP, Facebook Marketing