can we make money in facebook?

I only know one Facebook application where we can earn money. It's called CloudCrowd. You'll get paid by completing the assignments. But I do not have any assignments available so far, hence I have not earn any cents. I am not sure if it is legit or not. I suppose if it exists in Facebook, it should be quite legit.

There are a couple of Applications that claim to pay in cash but I have never seen proof and never have signed up for one. Other than that, I use Facebook just for the social aspect and use other programs to earn cash.