A few that I visited:
VampireFreaks Deleted, site turned into a Hot Topic clone
I was mostly on there to chat with musicians. Ended up making one IRL friend for a little while who happened to be in my area, but that didn't last since he ended up just wanting me to drive him places
//Rome.ro GameTalk, John Romero's Forums Deleted
The most notable thing that came out of this was that there was some guy named Corbin who would post about how he was making Daikatana 2. It was basically "hey, I made a team to work on D2. We're totally going to make D2. Where's the demo? Well we have a rather nondescript screenshot of a house asset. Oh no, team drama, gotta reform the team," rinse and repeat for like two years
Eventually, two members of the forum got fed up with him hyping up a project that obviously didn't exist, so they made their own "Daikatana 2" in a single day. It was a fully playable 3D game written in a custom engine. It was one room where you had to run around and collect some coins or something and the game would be over. It was rudimentary, but had lots of Daikatana references in it. They posted it to be like "We made a demo. Where the fuck is yours already?" Corbin fucked off for a while after that
Troniks/Chondritic Sound Forums Deleted
This was a popular forum for noise music fans and musicians, related to a noise music label. They had a really interesting DIY section where people showed off the different things they would come up with to make noise or affect sound. The forums were deleted over some petty drama, which is endemic of noise artist behavior
Zeuxworld Deleted
A forum founded around the game creation system MegaZeux, which was basically an advanced version of ZZT. The community was full of creative types, from programmers to visual artists to musicians
Probably the most notable thing to come out of this was that the site owner was trying to figure out how to make a script that would automatically log him into his admin account. He posted the code publicly asking for help with it, but it included his password in plaintext: "puddle". Someone grabbed it, logged in, and started screwing with the forums. Then the hacker logged in as the admin on IRC since he apparently used the same password for everything. People in the chat were trying to tell him that the site was being hacked, but he brushed it off. Shortly after he logged off, the actual admin logged into IRC and everyone immediately started accusing
him of being the hacker
Ultimately, owners and admins repaired the damage. One even commented something like "I'm surprised he didn't hack the FTP server since the password was 12345"
DigitalMZX Online, yet dead
Everyone migrated here after Zeuxworld shut down. Nothing particularly notable happened here from what I remember. The site is pretty cool since it lets you play MegaZeux games online without having to download the MegaZeux binary
Litany.net Deleted
Basically the #1 Skinny Puppy fansite online. There were a lot of cool people on there, but nothing particularly notable came out of the community
Craigslist Forums Active, unfortunately
Arguably one of the most incoherent and nonsensical places on the Internet
Foetus Official Forum Deleted
The official forums for the musician/band Foetus. I remember the forums being inexplicably deleted within a few days of someone pointing out that
the Foetus song Chimera was ripped off entirely from the Carrie soundtrack. Maybe these things weren't related, but the sole member of the band also wouldn't add me on MySpace until I changed my avatar to something other than the Pig logo, which is a band that he hates. I wouldn't put petty stuff past him