What are the risks?

Where and when are you at risk?
You're at risk when you're online, plain and simple. But some places are more dangerous than others – same as in the real world:

If you enter a government building you're most likely going to be ok.

Same if you visit Microsoft's site.

If you go clubbing there's a chance you'll get your wallet nicked and your teeth bashed in.

Same if you visit social sites like Twitter and Facebook.

If you visit an S&M prostitute there's a very real possibility that you're gonna get whipped – that's what you're there for, after all!

Same if you go to a porn site.

What are the consequences?
Social networking sites such as Twitter and Facebook are feeding grounds for cybercrime – among other things they are infested with links to sites hosting malware.
If you bump into one of these, and your computer isn't protected by at the very least good antivirus software and a great firewall, you're on the road to ruin: Your computer is an open door to virus writers, identity thieves, keyloggers, spammers and scammers.

What can you do?

Make sure you have good internet security software.
Make sure you keep all your other software updated continuously – old software is vulnerable to viruses.
It's a really good idea to backup of your valuable data to an online drive: Your papers and your dissertation are obvious choices, as are your photos and music.