If your site offers a coupon code or a spot on your checkout page where they can input a coupon code and you want to use it to tap into facebook traffic, keep reading... This is how it works: You install a php script on your web server that uses the Facebook Graph API, which a good pre-made script can be found at power130.com. Now, where you want to offer them a coupon code you put something like, "facebook users get a $10 coupon, click here". Now with the script from power130.com, once they click the "click here" link, it has them log into facebook and in turn they give you access to do cool things with their facebook account. You can have the power 130 script do 1 of 2 things to give them their code, it can email it to them using the email address they registered with facebook or it can redirect them to a page where you have the coupon code. Now with this you are probably thinking what good does this do me? Well, with the power 130 script you can have it post to their wall as soon as they sign up which can be a link back to your web site so now all of their facebook friends will see it and it will drive more traffic to your site. Another good thing about power 130 script is, you can log into the admin portion later on and do another wall post to everyone that has signed up to get your coupon code. Now you have the ability to promote anything that you want, when ever you want. I noticed the script is sold through clickbank so anyone that does web site design can use it for an upsale or something. Not sure on the commissions for it though.