With the release of Flash Player 9,0,115,0, there are lots of security changes are being introduced. Some are already there in the current release, more would be coming in later releases.
If your flash/flex applications require security settings for crossdomain data loading, cross domain scripting, socket connection or any other thing, you must read the Deneb Meketa’s article on Adobe Developer Center.
I am reading the same and believe me, there are lots of new stuff (terms and things). It’s good that Adobe is constantly trying to improve security features, though I feel, there can be more flexibility for Socket connections.