There was a pretty interesting talk presented at DefCon this year on tracking and other personal data being exfiltrated from mobile devices over Tor (in plaintext!!!). After noticing this activity on some end user devices, the presenters set up some exit nodes and started looking for similar traffic, and uncovered a shocking amount of data being moved about in this manner from a variety of mobile applications. Unfortunately, the presenters didn't name and shame (though they did imply some well-known brands were guilty), and it was presented at the SkyTalks venue, so no recording was allowed and the slides won't be published. But given the data that they were collecting and where the impacted users seemed to be located, it appeared like a majority of the tracking traffic they were intercepting was coming from users in China, Russia, and other states with civil liberties issues.