You've got Gmail!

Google's Gmail App has become the first Android App to cross one billion downloads on Google Play, the market for Android apps. This achievement was announced by Sundar Pichai, Google's head of Android, last week.

Google play ranks it's applications according to the number of downloads and categorizes them into different ranges. The Gmail app is now featured within one billion to five billion download bracket

The Gmail App is a default app in all Google powered Android smart phones except for those manufactured in China and therefore the billion downloads is also a count of the number of Android devices sold. Executives from Google claim that more than a billion android devices were activated last year.

Thus keeping Gmail as the most popular mailing service online for exchanging mail.