I myself prefer Instant Messaging.
It's an excellent form of communication, and just like the phone, you can block any annoying people. MSN Messenger is the best in my opinion, just one small ad on the contact list window and many features you can customise. One thing puzzles me though, people have extremely long and confusing names on my MSN List. Oh well.
Yes, there are always risks with every form of communication. The person you could be talking may not be who you think he/she is. But if it's people from school, or forums, then it could prove to be a vaulable form of communcation. I feel more safer talking on the internet then in real life. That's my opinion. Of course, you can't have a classy dinner on the internet, that's reserved for real life. I hope I made some sense in my post.