R K.

It's the most comprehensive site out there. Essential for tagging, release dates and versions, album art, etc. More usable than discogs. I really like the genres & influences section, the music focused bios and the ability to traverse from one artist to another in multiple places (hyperlinks in biographies, member names, influences). I find it more useful than Wiki. It is not as extensive ex-US unless acts make it to at least medium sized international labels. Don't use it to listen to clips, though. I use streaming sites to actually listen to things. But I agree with the others about the horrible pop up ads and commercialization. I just don't know how it could stay free otherwise.