How to use Facebook to market your product/blog/website

Recently, I received a few "add friend" request from unknown stranger in Facebook. When I look into their "Add Friend" request, it comes with message of their product/blog/website which they would like to promote. Well, I didn't like this kind of marketing as it works like spam mail. Even though some use pretty girl face as their Facebook profile and then try to add me as friend, I didn't bother