Last.fm - Do you know this site? Do you use it?

Last.fm - it's a site which count what are you listening to. Yes, I said what are you listening to, I mean you reg, then you download a small software with a winamp plug-in and you are ready! From now on your music will be charted. When you listen to a song, the Last.fm software add it to your page and after some time you got week charts, month charts, and even year charts. You have neighbours - people who listen to similar to your music, you can add your favourite tracks to a list, and your most hated tracks, too! It's cool, do you use it?