Google's Allo offers users messaging app with Google Assistant built in, offering automatically generated responses called Smart Replies and other computer-generated suggestions for your everyday life. keep them indefinitely, or at least until you manually delete them. That, Google acknowledged Wednesday, is a change from what the company told some reporters before its annual developer conference, I/O, in May. While the company initially considered keeping messages in a "transient" fashion, testing of Allo revealed that its Smart Reply technology worked better if it had a longer history of user messages to draw from.