Windows Live Messenger

Even if the name didn't contain the word 'Windows', I'm sure I'd be able to figure out that it was created by Windows due to the sheer dodginess of the program.

Ok, so perhaps that's an exaggeration. What I'm saying is that I can't figure out how to use it. Why are only 2 or 3 of my MSN contacts showing up? Can someone help me? If I'm using this thing at uni, I want to know what to do. Thanks.