Social engineering is the term used to describe any trick used to take advantage of inattentive or trusting people. It is essentially the art of manipulating people to perform actions or divulge confidential information. When it relates to IT, social engineering uses the additional cloak of "invisibility" through the internet.
There are many examples of scams, and here are a few:
Scams that used to be delivered by phone or mail are now being done online. Auctions posting non-existent or falsely represented merchandize, Nigerian money offers promising large sums of cash, financial scams targeting consumers with poor credit in hopes of receiving credit cards or loans, phony sweepstakes offers asking for payment for a prize that doesn't exist: all can snag the unwary or vulnerable visitor.
Predators and fake friends
Remain as anonymous as possible, which means keep all private information private; do not give out your real full name, age, home address, phone number, social security number, passwords, names of family members, or credit cards unless required for a legitimate business transaction. And learn how it's going to be used, and how it will be protected, before you share it.