What was your first community forum that you joined?
I think the first forum I joined was the official Baten Kaitos forums? I was...fourteen. Such a long time ago! It might have been the official Square Enix Forums though...I remember they had a light purple skin that I loved.
What makes you stay in a community?
I don't know, really. I used to stay on forums for the people (I made many friends in my teenage years on forums, and I miss them all...) but since I've stopped interacting with people on a more personal level, it's more the level/type of activity of the place these days. I like communities that are active and have more involving discussions about things. I don't really like forums that are primarily based on Discord and have a forum just because they think they should have a forum. Discord group chat makes me uncomfortable, and I've quit more than one forum because people only talk on Discord and let the boards die...then completely ignore you if you try and talk on Discord.
Overall though, I think it's the feel of the place? I used to prefer smaller forums, but I think larger forums are better these days because you don't have to try so hard to break into a clique of older veteran members who have been around for years and want nothing to do with you, and believe me, that's a very common attitude on older boards that are only active because a group of people can't/won't let "the good old days" go. There are still cliques on larger active forums, but there are many of them, and it doesn't seem to matter how long you've been on a place for; you can usually find someone to talk to, or at least get involved in discussion without feeling like you're intruding. There is a totally different aura to forums that make you feel welcome to those that don't. It's partly psychological, yes, but it's also in the general attitude and approach people have towards others they don't know. The larger the forum, the more likely you are to find someone who will provide an interesting discussion and won't make you feel like you should quit whilst you're ahead.