After using Android 4.1 Jelly Bean on my Galaxy S II for the last month or so, I've really fallen in love with Google Now. There are numerous 'cards' that I use, such as transit details for my day job drive into work, and the weather.
Google have now added in a new card, a pedometer, that tracks your steps and miles (or kilometres), all in the background of your phone. Droid Life are reporting they've noticed this happening in the background and the feature popped up as a new card - very nice.
The pedometer in Google Now compares months against each other of your fitness details, splitting up the activities depending on the type of activity you have done. There is a mention under the results that states "Based on your device's location which is periodically sent to Google".
I think this feature is great, and while I'm not a fitness junkie, it'll be nice to have this just happening in the background rather than being forced to download a separate pedometer application.