RCS is the legacy telcos ongoing attempt to try to somehow get into the messaging game that all of the Internet-based communications app are doing (WhatsApp, FB Messenger, Line, Kik, Skype, iMessage, etc.).

Basically, they'd like all their SMS revenue back!

Dean Bubley had a great analysis - "Google + GSMA announcement on RCS is no gamechanger" : http://disruptivewireless.blogspot.co.uk/2016/02/google-gsma...