We could not see any demo of the complete new Android M operating system at I/O 2015, but the Google team was showcasing the two main new features, namely Android Pay and Google Now On Tap.
Basically, Now on tap will allow users to get a number of contextual information while you are browsing your apps in Android M without the need to leave the need to leave the current application. This is particularly practical when you are texting, chatting or emailing with friends.
When you are inside an application, an email for instance, you hold the home button to display a card containing related information to the email content, in the demo,the first example was a movie question inside an email.
Similar contextual information can be triggered across multiple applications, the second example was shown from a chat application, and a few other applications were available from the Now On Tap Card to access additional information related to a place in San Francisco (Map,Yelp, Trip Advisor).
Users will also be able to ask for information suing the voice inside some apps, such as music applications.
Google pushed the concept of the virtual personal assistant on mobile one step further, the trade off is the lack of privacy while the system is tracking all your moves in the device. Unlike the browser it seems impossible to get an “incognito mode” since the access to contextual information requires the system to learn from your behavior across the applications.
Developers will be able to implement App Indexing for Google search to let users access contextual information related to their application through Now on tap. You will find more information about Android M in the official Google page here.