Image via CrunchBase
Their announcement is here. The key though resides with this as to how they differ from Twilio:
However, Twilio comes with a catch. App developers are locked in to their cloud and are left with no option when it comes to choosing their own carriers or their own hosting solution. This is prohibitive for some users who have since been scouting for an open source alternative. Therein lay the premise for Plivo – a 100% FOSS alternative to Twilio.