The T9 has doubled its efficiency year over year, it went from guessing your contacts surnames to auto-complete full pancake recipes, to reproposing embarassing chunks of real conversations. You can use it to autocomplete your homeworks, or pretend you did not copy stuff directly from someone else, or some successful Open Source library. You can use it to autocomplete secret girlfriends, migrants home address, someone else's credit card, or just as your own personal Emacs psychiatrist.