Armed with your mobile phone you are now a mobile sensor, careening along your footpath, reading your email, consuming your information, enriching your journey with timely recommendations as you dodge passersby. Tap. Swipe. Pinch. Zoom. Learn of the world.

And the world quietly learns about you, at least as organized by Google.

Don't be frightened. Soon you won't be wondering what else you can do with your phone, you'll be amazed by what it does for you.

At least that's the promise of GoogleNow.

Google Now is more of a mobile experience than an application, more of a search service than a search action. It could well redefine mobile search.

Certainly its name betrays its ambition.

But we're getting ahead of ourselves. For starters, Google Now is still learning. It gets some things right, and some things oddly wrong. In that sense, it's more like Google Soon than Google Now.

Google Knowledge Graph

I've been testing Google Now for a few weeks on a Samsung Galaxy Nexus smartphone and the Google Nexus 7 tablet. Google Now is part of Jelly Bean, the newest version of Google's mobile Android operating system.

It’s powered by Google's Knowledge Graph, unveiled a few months ago. As Google puts it, the Knowledge Graph creates connections between objects (entities) based on observed relationships and patterns--observed, that is, through Google Search.

(Fast Company offers up some insight into Google Knowledge Graph, while Mashable has some excellent insights into how Knowledge Graph could change the future of search.)

Today, for instance, when you search for penguins, Google presents a panel on the right-hand side of the search page showing the Pittsburgh-based hockey team or the animal. A subtle but important shift, Google would say, from being an information engine to becoming a knowledge engine. What's more, the search for "king penguin" provides rich information, including its scientific name, species and so on. The Knowledge Graph attempts to provide the information it thinks you'll want.

If the Knowledge Graph is about delivering the right content, Google Now is about delivering it in the right context.

How Google Now Works

There are three (and a half) ways to access Google Now directly: from the search bar on the Android home screen, from the Google app, and by swiping up from the bottom of the home screen (a bit redundant, frankly). Alerts driven from Google Now can also show up in the Android notifications (this is the half).

The Google Now interface provides a series of "cards," all driven by what Google learns about you, which is to say what you allow Google to learn about you--it's entirely an opt-in experience.

What this means is that your location, your searches, your travel habits (by car, using Google Maps and location services; by air, using your searches for flight status; by public transit using location) and your calendar data all get filtered, processed, and eventually understood (your context) and mapped to pieces of information Google might know (the content).

For example, Google Now follows your searches for restaurants, and as you drive about, it will pop up suggestions based on time of day (like dinner time). It learns your favorite sports teams, and creates cards that follow the action in real time. It knows the flights you've searched and provides flight status automatically. There are cards for currency (when it knows you're in a different country) and language translation.

Much of this capability relies on search, and while it can comb through your searches in the native Android browser, it can also use Google's Chrome. And because Chrome essentially maintains your search session state across devices, something you've searched for with Chrome on the desktop (or on an iPad) gets fed into Google Now on the mobile device. You have to be signed into your Google account for all of this to work, naturally.