Dalekboy

You only actually need to be welcoming to new people - the new people will take care of all the rest by themselves. Basically, this is what Swancon did right. The real Swancon old guard continue to (yes, even now, nearly 20 years later) bitch about anime and cyberpunk and such, and still like to play Rail Baron -- but it doesn't matter at all, because there were new people, and then new people after that, and then new people after that.