[hillsarealiv3]

That would be these agreements: http://bgr.com/2014/02/13/google-play-terms-of-service/

“the agreement places a company-wide ban on Android forks, saying OEMs are forbidden from taking ‘any actions that may cause or result in the fragmentation of Android’ and specifically disallows distributing or encouraging a third-party to distribute ‘a software development kit derived from Android.'”

Not so very open after all?

The people who have forked android have great difficulty finding OEMs to manufacture thrir devices as the list of those who don't have agreements with Google is rather short.

[AtlasLion]

No one ever said that Google's services were open. The operating system itself is open. instead of starting from 0, Yandex could just modify Android and have their own market, maps... People been bitching about fragmentation in Android for years, when google changed their agreement to counter it, people are now bitching about the agreement.

[hillsarealiv3]

The problem is that even if they create their own marketplace etc. any manufacturers who have an agreement with Google will be unable to manufacture any devices running the forked version. The restriction is company wide for the OEM.