Over at Mashable, there has been some discussion about the issue of Facebook Likes coming from fake people who are just robots that automatically like pages that are advertising for new Likes.
Well, I've been barking about this issue for a while now with our current members, and recently I wrote an article on how you can't build a sustainable marketing strategy on social media alone due to these kinds of issues.
You see, the trouble with these fake Facebook Likes is that they are just Vanity Marketing. It's just done to boost up the number of fans of your page so that it looks you've got a lot of them.
However, because these fake fans don't actually interact with your posts, you lower your overall engagement rates - the percentage of people commenting, liking, and sharing your posts falls significantly. And if your engagement rates lower, Facebook sees that as being a sign that you aren't posting good content. As a consequence, your post will show up in fewer news feeds, which will continue to lower engagement... It becomes a cycle of constant decline.
Ultimately, a little bit of Facebook "Like" ads being used isn't going to kill you, but it's not nearly as good for your page as organically getting Likes by getting real life fans of your work to punch the Like button for you.