I believe that some online forums have lost the luster as you say.
Let's take gaiaonline.com for example if you go on there now all you find are horny 15 year olds that mainly it. Well they are not the only ones on there but mainly the 15-18 age group are the worst. It's like your having a normal conversation and then out of the blue they try to start something. (Keepin it clean) About 2 years ago it wasn't this bad I mean yes there were people but then all of the sudden they were bum barged by the horniness. To start out with the site was just somewhere to have fun and chat with people on there. I would like someone to just go on there as a guest or something and see all the topics it's sick. What happened to the family forums you know get to know someone and become friends?
Now we take Anime Online the only thing I see that it has lost members because they did not want to cope with the changes. Yes there are some people that are like scared to put in topics because they don't know if people will even reply. Due to the fact they think they are the only one with interests in the topic or they don't know how to start the topic off. This forum is coming out of a Great Depression state but it's still a place that people come to talk about common interests. They see this as a family site and want it family friendly.
I hope this is what you were looking for or something of the nature.