I call it T2T..
It's like an online mesaging app like viber, imessage, hangouts etc.
Were textra itself detects people on your contact using textra. And allowing to send/receive messages using data or wifi connection.. Well its not really an idea but a suggestion because a lot of apps out there offering such.. So why can't textra? Everybody loves textra including me.. This would be a major addition to the application. Hoping the developers would take this as consideration for future updates.