What is "Now On Tap"?
Hi claus. "Now on Tap" is not yet what I'd call a household name. I've even seen comments suggesting that it may be too obscure a feature to catch on, yet many are discussing it as the next big breakthrough in search.
As I understand it, "Now on Tap" is an extension of "Google Now", one which has been evolving along with Google's Android operating system and also in parallel with Google's app-only indexing capabilities. Clearly, a lot of planning and forethought have been put into this feature.
Triggered by tapping and then holding the home button of an Android 6 (aka Android M or "Marshmallow") mobile phone, "Now on Tap" performs a context-aware search of whatever web or app content is on the screen of the phone at the time. Google has been making a gradual push to publicize the feature and to expand its capabilities.
Chances are that if you haven't been using Google much, it's unlikely that you'd be using a phone running Android 6.
Interested SEOs should know at least how their apps can get indexed by Google. Here's the earliest official reference I've found to "Now on Tap", from about a year ago.... "Now on tap" to help you with what you need in the moment, anywhere on your phone May 28, 2015
We're working to make Google Now a little smarter in the upcoming Android M release, so you can ask it to assist you with whatever you're doing -- right in the moment, anywhere on your phone. With "Now on tap," you can simply tap and hold the home button for assistance without having to leave what you're doing -- whether you're in an app or on a website....
...When you tap and hold the home button, Google gives you options that are a best guess of what might be helpful to you in the moment. But if you need something specific, you can also get Google to help by saying "Ok Google" from any screen, and any app....
...And best of all, developers don't need to do anything to integrate with Now on tap as long as they have their apps indexed by Google [firebase.google.com...]
We've had various short discussions on this forum regarding Google's evolution toward app indexing, but we haven't addressed this in the context of "Now on Tap".