[Google I/O 2013] Google announces "Google+ Hangout", their unified Messaging service
Google has taken the wraps off of one of the most anticipated services, Google+ Hangouts. While it bears the name of the existing video service offered by their social network, this incarnation of Hangouts is the unified messaging experience that Google took far longer than anyone thought to release.
Compatible with Android, iOS, as well as on Chrome, Google Hangouts is synchronized across all those platforms. So a chat happening on one device will be synced on another device as well as only notifies the actively used device via new Play APIs announced by Google today.