Virtually all mobile viruses affect Android, largely because no one really vets the apps in the Google Android app stores. So, developers can put up apps that steal data, or point you to malware sites, and nobody stops them. But Virus Shield to the rescue! It...well, it does nothing. But it was the top-selling app on the Google Play store, so it did that. From the WaPo:

Android users collectively spent $40,000 on an app that does nothing.

For $3.99, Virus Shield promised to protect your phone by scanning apps, settings, files and media for viruses in real time. All that without pesky advertisements or draining your battery.

It sounded too good to be true — and it was. But that didn't stop 10,000 people from downloading it, making it the top-selling paid app among Google Play's offerings for Android.

It got an impressive 4.7 star rating from users. To be fair, the app did do one thing reliably well: it could change the image of an "X" into a "check" after a single tap. Unfortunately that didn't mean the app actually scanned and checked your phone, according to Michael Crider at Android Police.

Shocking to no one: the Android app store is full of crap