Are you looking for a social group to get together or a bunch to send out incident alerts?
There is Twitter, Facebook, Group.Me, Meetup, Yahoogroups (yes), and whatever other technological means available that there is splintering of any hobby groups that exist. Add to that the paid services and you have a mish-mash.
When I was running my Fort Lauderdale and east Broward County feeds full time I would tweet incidents that were worth notifying about.
Now there's PulsePoint for Fort Lauderdale fire to steal your thunder there.
Look into IPN paging I am a dispatcher there and there is a few dispatchers there that have excellent coverage of Broward county, Orange county, Dade county and decent coverage in Martin county, I listen to Indian river county and page there (Im from CT) but the feed been down for an unknown reason. The service is cheap and you can become a dispatcher there also and put out calls you hear. There is one guy on the system that is on the tri county rehab unit and pages tons of calls in the Dade, Broward county area.