You've probably seen those innocent looking Facebook posts that ask you to "Like" a page in order to "help so and so get her kidney transplant!".
You want to help so you click "Like" but most of these pages are scams and once you "Like" them, your friends will see you fell for it and worse yet, they may get roped in as well.
Once these pages have enough "Likes", they're sold to businesses who use them to make their own pages more popular or they're rebranded and sold to unscrupulous marketers who may even use them to spread malicious software.
Cybercriminals prey on Facebookers because people are much more likely to trust links that are unknowingly spread by their own friends. Be careful what you "Like" on Facebook as scammers are everywhere!