One of the most effective methods that hackers use to identify potential prey, is the copy-and-paste social engineering trick. Facebook is a goldmine for just that. The more gullible someone is by nature, the easier and the more they'll fall for it. And that's the target market scammers love.
Take a look at the below post from one Wendy Botes that I came across on Facebook this afternoon. Will use it as example of how dangerous it actually is. Below it, a very important message you need to get into the heads of your friends.