Not sure if this is a documented feature but you can search within Google+ Communities by adding s/yoursearchterm to the community home address (operators like AND/OR also appear to work).
A look at the Google+ Hangout API which enables you to to create you own in-hangout applications and alternative solutions using widgets and 3rd party APIs
More notes from Google I/O 2012 from an introductory session on Google+. As well as finding a better starting point for Google+ buttons/badges the session was an opportunity to meet +Ade Oshineye and hear about Google +1 Recommendations
Hangouts On Air are broadcasted live to Google+ and YouTube so anyone can watch even if they don’t have a G+ account Participants who can join the hangout for On […]