I joined around 2004 and I'm 25 now. I just started visiting again after quite a few years, for nostalgic purposes I guess. I'll probably stop and start again at some point.
It's like a strange, modern way to relive your childhood.
There are probably adults who still use this site...but I'm not one of them. I joined this site in '08 as a fourteen year old, I'm now twenty. However haven't been active in over two years. When inflation reached the point where Gaia (in practice) became pay-to-play, I lost interest. The avatar customisation was the main thing that kept me here. It's strange to think now that this place was such a big part of my adolescence!
I was 17 when I joined in the Summer of '04.
I just turned 28.
I think the inflation makes it less fun now.
I take several breaks per year and come back every few weeks
for about 2 days. I get bored with it and leave again.
Gaia didn't even exist until a few months before I turned 18, so I'm definitely an adult...
I joined in 2006, shortly before I turned 21. So that makes me 29 now. Most of the people on Gaia that I know are over 20, and many are up into their 50s.
Can't remember if I already posted here or not. I'm 33, have been here for ~11 years (since August 03 -- this is a new account though). I'm married and have a job/life/etc. Gaia is pretty much my "I have some time to kill" web site now. Sometimes I just don't want to deal with grown up stuff like the news, etc. so I come here to dress my avatar and talk about items. It's not a huuuuuuge part of my life anymore but I have no plans to quit either, if that makes sense. It's familiar and comfortable. I've lived in 3 countries since making an account here, so Gaia was kinda my familiar space (my "home" if you will) between the 3. I still occasionally toss some money their way because I want to support the site, and I'm a Verge member.
A lot of people judge the older gaians but honestly coming here in my free time isn't any different than playing a game or reading a comic book. It's just a fun thing to do.