Gary Illyes from Google posted a question for webmasters on Google+ and Twitter asking if you or you know anyone who uses Angular JS without escaped_fragment.
It makes you wonder why he is asking?
Is Google looking to make changes to how they index and rank web application and pages built using Angular JS?
Not too long ago, John Mueller from Google participated in an Angular JS hangout with developers.
Maybe Google is looking for more efficient ways to go about indexing content there?