The first forum that i regularly talked in was one called Firefly.  It was a long time ago I used to talk there alot.  I believe they shut down in 96 or so but I really liked talking there and I had several friends.  After that I drifted around some and then I landed on Delphi forums.  I had alot of fun there and I met some real good friends in fact I met my two oldest online friends from there Michowl and Wolf.  After delphi got a bit funky and changed up alot I left that site.

But back on subject Firefly was my first one i was at.  How bout yall 

Penthouse Letters

http://www.truemeaningoflife.com/forum/

though I didn't use twesterm back then...

Gameglow.com's Legend of Mana boards.

I don't know how LoM got boards there other than being tied to a fansite that was constantly opening and closing. Around the end of 2001 I believe, Gameglow suddenly shut its doors. I think the admin were caught in some kind of scandal, they were being very suspicious and couldn't talk about it. To this day, I still don't know what happened there or why they had to close so suddenly. The actual community on the LoM baord has jumped from board to board to this day, losing people each jump. It's now a shadow of its former self and I haven't posted in over a year.

gamefaqs.com

years ago I had AOL and frequented the Islamic forum. Next to video games one of my favorite topics is religion, in general, not just Islam.

It had to be a bodybuilding forum on AOL or something. Although, I quickly moved to newsgroups. Aww, the mid-90s...

The first forum posts I can remember doing are a couple specific threads in neoseeker, but I may be forgetting something earlier.

The first forum I posted on regularly would probably be Moz La Punk, which grew from a forum-equipped blog to a news-format website at mozlapunk.net; now it's just a lightly-populated forum under the umbrella of www.armleg.com.

I discovered that site when it was in the news-site stage, and took to posting extensive spelling/grammar corrections of news items. Eventually, Moz La Punk himself suggested I be their official proofreader, and I took him up on it, but that only lasted a few months before they shut down that aspect of the site due to lack of dedicated writers. I moved on to Kotaku and Joystiq for my gaming news but never was part of any other forums until this place.

Gamefaqs. More specifically, the Star Wars: Rogue Squadron II board. Good times. :)

Mangaheuvel.

Belgian site with a forum about manga .