What are the dangers online that we should be aware of?

Here are several application types that lend themselves to abuse by unsavory types. The seminars cover all of the ones I am aware of. They are:

• Chatrooms.(IRC) Programs that allow you to talk to anyone, anywhere, anonymously. People can pretend to be whomever or whatever they like.
• Instant Messengers. (ICQ, AIM, MSN) Chat and messaging programs that have many of the same problems as IRC.
• Spyware. Applications given for free that secretly track your movements and preferances.
• Virus's. Small programs designed to infect as many computers as possible, often automatically emailing themselves to everyone in your email address book. Virus's can do pretty much anything, from wiping your hard drive to putting a smiley face on your desktop. unfortunately the former is more likely.
• Spam. Email you didn't ask for, from people you don't know, about things you don't want. (often graphic porn), and often using Spyware techniques.