Same here, phpBB and vBulletin are basically what kick started my career, though I had built a ton of small static html sites before when I was in HS. I built a small but still pretty big community. I think the board ended with ~30k users, not all active, but still. I only just shut it down a few years ago. Reddit essentially killed it, and once I actually got a job it was harder to maintain my presence there and keep up with the personalities. Never made a dime from it, but it ended up being a solid investment.

I still have all of the files, etc, the database is a monster. So, I could theoretically put it back up. Took it from phpBB to vBulletin 3.6 to 4 to 5, so it was an older and long lasting. I remember setting it up my freshman year in college ('06) taking advantage of a protest of moderators on a different board (they were reading user's PMs). Some of my favorite internet memories came from internet forums. The thing I always hated about vB though is that even a minor update could cause part of a custom theme to break, and the CP felt dated, even in the early 2000s. Finding a theme template or option was so overly complicated.