Karissa Bell, Mashable:
[…] the problem is not that Unroll.me was scraping data from users’ inboxes and selling it (in anonymized form) to third parties, but the lack of transparency that this was happening. The company’s entire business model is predicated on data collection but nowhere on the company’s app, website, sign-up page, or anywhere else was that made clear. (Hedaya has said he plans to address this.)
Think about the laws and common-sense ethics that are skirted when it comes to data sharing. Practically every web service stretches what they can get away with, requires opting out of practices that users may find objectionable, and only requires opting into something when it’s required by law. Just look at the super gross “Dark Patterns” that try to trick users into allowing their information to be shared and sold widely, with little oversight.
I can’t think of anyone who would think that this is a good idea. I can think of lots of people who see this trickery as profitable, but who actually believes that these now-commonplace anti-privacy practices are ethical, or something that they would like to be subjected to as a user?