I always wonder about the "reports" that smaller companies produce. At Y! the research group (as in customer insights) are proper statisticians and know how to do sampling, and discard outliers, etc.

I'd be much happier if some of these companies published raw anonymised data with their methodology to accompany the report.

Right. The users must've downloaded at least one app to participate in the survey, and it's not unreasonable to assume that people willing to complete such a survey would be at the extreme end of app activity.