Google has fundamentally changed the way its own app ecosystem works in order to put pressure on manufacturers and ROM users to certify their Android device. Primarily, the goal here appears to be the creation of a more unified platform and halt the unauthorized distribution of its wholly-owned software. Android itself may be open-source and able to be used in an unlimited number of ways but Google's Play Store, Gmail, and other apps are not. Given the sheer number of device OEMs and ROM developers, some of those are bound to be less-than-reputable. So it makes sense that the company would want to ensure that devices running its applications meet certain criteria. Moreover, if a company or individual is making money and including access to Google's proprietary software, it makes sense that the search giant deserves to know about it, at very least.
As to how exactly the company plans on implementing its new policy, that's relatively straightforward. Upon installation of Google's applications, the software will check a device's Android build number and date. If it doesn't recognize the version of Android as certified and the OS was compiled after March 16 of this year, the software simply won't work. As mentioned above, that simple measure should make it far more difficult for a company to get around Google's licensing. However, for those who prefer a custom ROM to stock Android, it could create a problem because of the custom build numbers and dates associated with those. Each ROM could end up treated like a separate device and there would be no simple way for those users to get around it. If they want to use a custom build, they will need to register the device with an Android ID, just as an OEM might need to do. The catch is that there are only 100 devices allowed per individual and some power users would easily burn through those certifications within a year.
Google, in the meantime, has yet to clarify the terms of the new policy and measures to prevent the sideloading or unauthorized use of its apps and services. So the breadth of this new policy isn't immediately clear and the idea that it will be disastrous for power users should be taken with a grain of salt. In the meantime, anybody interested in checking out the certification form for themselves can click the button below.