Potential Threats of IT
If you register to unsafe sites or when you download unsafe documents you usually get virus. With anti-virus programs you could relase them.
Spam can be defined as unwanted messages or emails. Probabyly when you visit insecure websites they get your private information and email adresses and they send you unwanted messages, mails, etc. There is some programs to block these spams.
Phishing is a kind of stealing people's personal information like their credit card informations. Be careful and don't give that kind of information to unsecure web sites.
There is a lot of threats in the big IT world and you must be careful of these threats.