A Facebook scam this week highlighted the threats posed to the millions of users of the popular social network. Security experts say users of social networks and Facebook, in particular, have high confidence in the links and information shared there. Attackers are constantly trying to take advantage of the high levels of behavioral trust, according to security firm Bitdefender. While Facebook has security teams and automated systems to detect suspicious activity and contain threats quickly, third-party app baits, spam, Likejacking and other activities persist, said Catalin Cosoi, head of the online threats lab at Bitdefender. Here are six signs you may have fallen prey to a Facebook scam.