Practically everywhere you can see this thing going on and meth programs are no different. Around every meth program develops an alternative scene where the clients meet and hang out in defiance of the program rules which require that clients come into the clinic and immediately leave the area afterwards. Gossip and news are exchanged, money lent and children baby-sitted. About the culture that grows around the clinics, I think it's the same in the straight world. It's known as kissing ass, back stabbing, gossip etc.
Nothing changes anyway.
Because this unofficial space melts into the larger street grapevine in the same way that a stream feeds into a river, it becomes an important, if unacknowledged, part of that grapevine. This grapevine shouldn't be underestimated. I can give a small example from personal experience. In the late 80s, through their informal networks, meth program people probably did more to circulate accurate information about preventing HIV than any of the official funded outreach programs ever did, including the one I was then working for. Once you look at the big picture, a strong argument can be made that in one way or another drugs are THE main economic engine keeping the city going.