Yeah, I couldn't join a board that was centralized around something I only like some aspects of or only have a casual interest in.
Like Pokemon, or Sailor Moon, or some other series.
Admittedly what really attracted me to this forum besides my massive love of Megaman back then was the fact that the community here was pretty mature and I felt that I could learn something by participating in the forum. Even though I was a massive n00b back then and was a bit sensitive to things, not to mention the fact that this place was my first real interaction with the internet so I didn't even know how to copy and paste, save pictures and other embarrassing things that I didn't know at the age of 14, but after a month I was able to adjust to here and haven't been to another forum since.
The reason I would never go to a Pokemon Forum is that I know that the user base would not be as mature or friendly as this one.