Who’s there? PubNub Presence knows. PubNub Presence detects when users enter and leave your app and gives the online/offline status of machines and devices connected to your app or channel. However, it does more than take user attendance. Presence also can automatically send notifications based on occupancy, can be used to trigger events based on audience size, and much more.
Check out the full introduction to PubNub Presence here: http://www.pubnub.com/blog/introducti...