I joined when I was 13 (under different accounts, to be certain). Now I am 19. I've done nothing major since then, except what usually comes with growing up. I have a feeling I've matured a lot since then, but people always assume that they have become better people in the present than they were in the past. Otherwise people realize the years they've wasted by making themselves worse, and depression follows soon after.
The forums have motivated me to basically improve my skills as a modder, though I still have yet to actually put forth the fruits of my labors because nothing is good enough yet in my eyes. Other than that, I've decided that sticking to the Community Discussion is much more worthwhile than slowly killing my brain cells in Skyrim General.
I have plenty of friends and other acquaintances in real life I still talk to, but it's nice to have some anonymous discussions with strangers I don't know. It's good to talk with people who don't actually know me, who probably won't say certain things just for my benefit. I like to stop once in a while and figure out whether or not I'm actually a terrible person through some good old self-anolysis. Better to do that here where people can say terrible things to and about me and get away with it