If you're the sort who already worries Google has too much of your personal information, this is not for you. For everyone else, Google is reportedly developing a new opt-in data collection service that will reward users for passing additional mobile usage data back to Mountain View. The so-called Mobile Meter app is expected to come to both Android and iOS.
Android already provides Google with various bits of data like location and search activity. Mobile Meter would presumably go much farther, perhaps monitoring which sites you visit and which apps you're using. The data would be anonymized and fed into the Google machine so that it may better understand us.
It isn't clear what kind of reward users would get for playing along – maybe Google Play credit or Wallet funds? Whatever it is, Google's going to have to make it pretty sweet to get people on-board.