Facebook ads target users “likes” as opposed to keywords like Google AdWords. As an advertiser you can pick specific fan pages to target their followers. For some businesses this is highly effective.
Give it a try for FREE. Here is a link to get a $50 ad credit. You can cancel anytime, even before the $50 is used up. This is for a limited time so hurry! Log into facebook and copy and paste http://on.fb.me/zWrYdD into your browser. Or click on the link after logged in. Clicking on the link without being logged in will not bring up the coupon.