You have to be impressed. Over one billion downloads for the Android Google Play app. It is worth noting though that with over one and a half million ratings which is a pretty good sample size the app only gets three and a half stars. You would think that Google would have had enough feedback to improve the app and up the rating to five stars for something with that many downloads.

Apps to blow your mind (ish):

Cycle gear
collaboration using Google Docs simplifies takeaway order