Fun anecdote time.
I worked on (and very briefly ran) MP3.com after the CNET acquisition of the domain (CNET only bought the domain, which I think was for $1 million). It had nothing to do with the original site mentioned here (good on them for archiving it).
The initial idea of the CNET version of the site was that in 2004 we assumed you would need a directory of which music was on which service. At the time there were quite a few (itunes, recently legal Napster, Rhapsody, eMusic...etc) and the thought was that the labels would sign deals separately on each, splitting where legal MP3s could be bought. Rhapsody was the only one where you paid a monthly fee for access, the rest were pay per song or album. The directory was similar to something like justwatch.com now, and it was really hard to build the data catalog from the early Internet spiderweb of music content from these services. Believe it or not, we got most of the data from FTP drops from each service. The site also would review all the different MP3 players of the time (there were a lot of them!).
The iPod and iTunes devoured the industry to a degree that no one needed such a directory. Everyone was happy to pay 99 cents per song, or get it illegally. Rhapsody, which was way ahead of its time, was too niche, and pre iPhone, no one could "stream" on anything buy a computer.
Everyone of course hated our new site. It didn't carry the spirit or the catalog of the indie bands from the original version (we didn't own any of the rights to keep the content), and all of those artists were rightfully very angry about losing a pay stream (which again, was a nod to what was coming later with YouTube partners). It got so bad that we had to remove the message boards completely because it was pure vitriol. We later added independent artist uploads, but by 2005 it was too late and the site mostly made money converting "eyeballs" (search any artist + mp3) into money through ads.
Despite all this, I had a lot of fun working on it, and as a young 24 year old who just moved to San Francisco it was a great way to learn about online communities and how they could turn on a dime. Other, later sites of mine took the lessons learned from MP3.com and became successful, but I'll always have a soft spot for MP3.com.
Here's a screenshot from the site in 2004! https://www.davesnider.com/file/d979a4b48bb