Google has started rolling out a new version of the Play Store (v6.7) that makes it easier to join a beta program for an app and provide developers with direct feedback about it. Up until now, signing up for the beta test of an app through the Google Play Store redirected one to a Google Play Store page inside a browser, which did not provide an intuitive and cohesive experience. Not to mention you first had to go through the tedious process of finding the link to join the beta program of that said app.
With the latest version of the Play Store, Google is making the whole process significantly easier. The listing of an app itself in the Play Store will provide one with the option to join the beta program and become a beta tester. The whole process takes place inside the Play Store app itself and you are no longer redirected to a new tab in your browser. The option to join the beta program, however, will only show up if you are a part of the Google+ community of that app or if the app developer does not have any such requirement.
You also have the option of leaving a direct feedback to the app developer that will not be visible to anyone else. The update also adds the option of leaving the beta test of an app that you are already a part of. Sadly, the option to manage all the beta app testing programs that you have joined so far is still missing. (Source: androidbeat)