Google has been working on the Smart Reply for a while, and we first got a glimpse of it with Inbox by Gmail, before seeing improved versions in Google Allo. The said algorithms take a peek at your incoming emails to understand the text and then suggest you very short, three to four-word replies at the bottom of the email screen itself.
According to a press release announcing the feature, users can choose to send one of the provided replies immediately, or they can edit and customize the message before sending.
You probably remember the Smart Reply feature that devices with Android Wear have.
Smart Reply works pretty straightforwardly.
If you give Smart Reply a try and decide it isn't for you, you can always turn off the feature in Gmail through Settings.
Inbox by Gmail has had Smart Reply for awhile. The team uses a hierarchy of modules, each of which processes inputs and provides transformed representations (and so on for each level). It will roll out globally in English first, with Spanish to follow in the coming weeks. This was very effective in many contexts but required substantial computation resources.
Using machine learning, the tool will begin to predict responses that are more in line with what the user would actually say.