Bugaboo: Hey, if you're asking about joining a game, come back and check your messages!

This has got my hair in a dander.  I am now hesitating on giving people invites until they have engaged in at least one response to a message from me as the GM because I find that some people post a message and then entirely disappear from the site, just wasting my time.  If people can't be bothered to check their messages here, I'll find someone else from the campaign who will see if they're invited.  I'm not going to leave dangling invites and get my game over-subscribed when people show up a week or two later.

Don't be a Bugaboo! Be kind, rewind and don't be that guy, reply!

I hate that as well, but in all fairness, sometimes real life emergencies do come up. My rule of thumb is that, if they do not respond in 5 days, I consider them gone for good.