In a shocking move, Google has recently deleted AdBlock Plus from the Android Play Store. This is hugely disappointing because it demonstrates that Google is willing to censor software and abandon its support for open platforms as soon as there's an ad-related business reason for doing so.

Until now, the Internet and software development communities have relied on Google to be safely on their side when it comes to building open platforms, encouraging innovation, and giving users maximum choice about how their computers will function. But with today's news, that commitment to openness suddenly looks much, much weaker.

Google clearly has a vested interest in preventing people from installing ad blocking software like AdBlock Plus.1 But until recently, the company did an admirable job of leaving that matter aside and letting users make their own choices about whether they wanted to hide ads on their phones and in their browsers. Google established a reputation for building tools that put the interests of their users first. This new form of censorship is the exact opposite. It is not only a betrayal of the principle of openness, but a betrayal of the trust that people put in Google when they decide to buy an Android phone.

Google's stated reason for the ban is that the Android app allegedly "interferes with or accesses another service or product in an unauthorized manner." This policy is broad, vague, and arbitrary. It isn't clear yet how far Google is going to go in censoring the Play Store. Are they just going to target ad blockers? Ad blockers are not only useful and extremely popular, but also currently the only way that Internet users can effectively protect themselves against non-consensual third party tracking. Or is Google going to follow the letter of its policy closely, in which case we would expect to see other useful privacy-enhancing technologies blocked from the Play Store, such as the apps that control the permissions of other apps (for instance, preventing the Skype app from tracking your location or the Foursquare app from grabbing the contents of your addressbook) or a hypothetical future port of HTTPS Everywhere? 2

Google may try to reply to this criticism by saying that on most (but not all) Android devices, there is still a way to tweak the system settings to allow installation of AdBlock Plus from outside of the Play Store. This is of limited reassurance. Making it hard to install useful software will have the concrete effect of greatly reducing how many people actually succeed when they try to do so. This is the kind of manipulative attack against openness that we've learned to expect from Apple, but we're extremely distressed to see it from Google.

For developers on the Android and other Google teams who are reading this, we urge you to rethink this terrible decision. Stand up for users. Don't let Android take the dark path. Don't be evil.

• 1. Although it's worth noting that AdBlock Plus isn't hostile to all advertising-based business models and only blocks a fraction of Google's ads by default
• 2. There is currently no HTTPS Everywhere port for Android because the OS lacks an adequate API for implementing it elegantly on non-rooted devices. Certainly, those apps could be argued to "intefere with other apps" just as much as AdBlock Plus does. From a user's point of view, the question is not whether an app alters the behavior of other apps, but whether the app does what the user wanted it to do. In the case of AdBlock Plus, the answer is clearly "yes". Actually, ABP on Android is flawed on non-rooted devices because it doesn't interfere with other apps as much as the user would want it to. That's a result of restrictions that Google has built into the Android API.