Play Newsstand has been installed over 1 billion times. That's a pretty big number. Let's take a moment to let that sink in.
Now let's take another moment to consider what this means. These aren't a billion unique users or a billion separate Google accounts. These are simply installs, and for the sake of these numbers, shipping on a device and getting automatically updated on first run counts as a new installation. With the number of Android devices I've used over the years, you could count me for several of these installs on my own.
Play Newsstand launched in 2013 when Google merged together Play Magazines and Currents. The app continues to provide content from blogs and print subscriptions in the same place. Has it attracted a billion active users? Not really. But congrats nonetheless.