A new messaging application called Strings has been introduced that will let people un-text users. If messages are shared using the application, users can actually have an already sent message erased from all devices involved. This could be great for those who don't quite think before typing.
Strings' text removal feature only works if all parties are using the messaging application, and since most people are not going to install Strings, the majority of messages cannot be retroactively destroyed.
When messages are erased, Strings says they automatically leave all phones as well as the Strings servers.