that's a wack introduction lol.
last.fm is a website that tracks the music you play. on the website you can listen to a webradio, or you can download an application for the radio. you can tag songs and after a while the radio will try and play songs similar to the ones you like. you can customize it in many ways though.
there's also an audioscrobbler that you can download and install as a plugin to winamp, itunes, wmp or whatever you use. that will submit the name and artist of whatever song you're playing when you've played half the track. all the songs you listen to get stored on the server and in your profile you get statistics like what songs you've played the most and such.
for people who download and listen to a lot of music, it's a) sorta cool to get the statistics as it doesn't take up any computer resources at all, and b) nice if you want to expand your horizons. it's a great way to find artists to your liking and to connect with other music listeners. not that i tried that but still, the idea sounds fresh when you're trying to sell it.