Comment by jadbox

You can still install apps outside the play store, but the developer does need to verify their signing information. Effectively this means that any app you install must have a paper trail to the originating developer, even if its not on the app store. On one hand, I can see the need for this to track down virus creators, but on the other, it provides Google transparency and control over side loaded app. It IS a concerning move, but currently this is far from 'killing' non-appstore apps for most of the market.