Google announced many improvements to its "machine learning" or artificial intelligence capabilities with Google Assistant. Google has already been learning about its users preferences and delivering relevant information through Google Now.
Google announced a new messaging app called Allo. The app has an assistant built-in, making it possible to ask it questions and complete tasks right from within the messaging app. For example, you could find a restaurant and make reservations there using the assistant. Google also built-in strong encryption, the same that is used by WhatsApp. This isn't used by default, however, and you need to start an "incognito" chat.
Another new app announced at Google I/O is Duo, which is a video chat app similar to FaceTime. It has a new feature called "Knock Knock" which turns on the camera so that the person receiving the call can see you before answering.
Both of these apps will be available this summer for iOS and Android.