When it comes to app download milestones, we like to celebrate the 500 Million and 1 Billion mark here on Android Police and more often than not, the apps are from Google's own portfolio which gives them a significant head-start on the competition by the mere fact that they usually come pre-installed on all Android devices. We've also seen Facebook and WhatsApp hit the 1B milestone, and Skype and Instagram and Dropbox reach 500M.

Still, this amount of downloads is out of reach for many apps and only the elite popular ones can get to it. Now, we're celebrating the 500 Million downloads milestone for two apps you've sure heard about: Twitter and Viber.

Viber unlocked the 500 Million downloads badge on April 10, according to AppBrain, and Twitter followed two weeks later on April 23, also according to AppBrain. They're still though far from the 1B achievement of their competitors, WhatsApp and Facebook. Either way, here's a big congrats to Viber and Twitter and a wish for more growth and users. I'm going to help them do just that by posting their widgets here so those of you who never installed them can get them now.

Developer: Twitter, Inc.
Price: Free