Facebook fans are great, but there are a few things you should know:

* Some people "like" everything.   If you are paying for fans, understand that you will buy a lot of very friendly people who also like a lot of other companies.

* Facebook is push marketing.  On Google, people are actively searching for you or your product.  On Facebook, they see your ad while engaged in something else.

*  Not sure if they still do this, but Facebook was opening a new browser for ad clicks.  Many people close the pop-up immediately.  I had much better luck when I sent people to my fan page.

*  There are real people out there who will interact with you through Facebook. 

Every market and customer is different, but there is value in Facebook marketing.  Just not as much as some people think.