After joining a few different Classic servers only to find 'blockhell' in each one, I came across Team9000.
I ventured in,
built a few things, helped others and enjoyed my time there.
Few days later, a bunch of the guys requested/demanded that I jump onto to Mumble server, which I did.
And the rest is history.
I've been in plenty of different online communities and I would have to say this has been one of better experiences of my life.
With a friendly community, mature users (most of the time), who are generally quite respectful to eachother, mix in an interest in gaming and you've got yourself a winning c-c-c-combo breaker.