We've found that the college age forum grew most quickly and is very active. College age people tend to have access to e-mail and feel comfortable communicating that way. When I helped get it started I noted that many of the conversations were around upcoming social events and keeping in touch. I do know that the forum remains fairly busy. The Fellowship forum is our BIG experiment.
Postings seem to come in spurts.
Topics vary from very serious to jokes. I've seen REAL community start to happen and then stop and then start again. The challenge is getting people to subscribe and getting them accustom to this type of communication. Like answering machines and voice mail, new types of communication take some getting used to. Once people get the hang of it, they seem to like it.