facebook group might work but for security reasons I think a lot of people would be sketched out about it. Do any of you guys chat on IRC? I think that might be better? According to this:
http://www.uer.ca/...urrpage=1&pp#post1 the official channel is #urbex on DALnet...I'm "happy_day" on there.
*EDIT*
The only problem is DALnet sucks. I just got kicked from the channel for idling in there for only 5 minutes. EFnet is way better, and the server I use the most. I'm also in #urbex on there.