100 members in 8 months is really quite a feat, considering the small audience we serve (most forums have an international audience for an internationally popular topic). It's certainly gone ahead better than I expected. We're now a long way from the early days, where I would sign on as two different users and talk to myself, to make it look like there was some activity here in the hope of attracting other members.

And it's a long time since I've felt compelled to answer every question myself, even the ones that I know nothing about, just to make sure new members got some sort of answer.
However, I guess now is the time to confess... the first 3 members are me, and the next three signed up under direct coercion from me. But that's what it takes to to get started. Nobody wants to join a forum with 1 member, and no activity. The next approximately 20 signed up after a post to a fly fishing forum pointing to here (written by one of those I coerced to join who frequents that fly fishing forum). That was a big boost for us, and it also explains why we have a large population of fly fishers here.
A competition? Could be a good idea. What should the prize be? A special rank in the forums for a year? If it was anything more substantial, we'd have to figure out a way of making the result less easily rigged by signing up under multiple names.