Earlier quoted context omitted.
I worked for a company that nearly acquired unroll.me. At the time, which was over three years ago, they had kept a copy of every single email of yours that you sent or received while a part of their service. Those emails were kept in a series of poorly secured S3 buckets. A large part of Slice buying unroll.me was for access to those email archives. Specifically, they wanted to look for keyword trends and for receip…
In terms only of capabilities, that makes me wonder a lot about Gmail. I don't see anything there that they couldn't do if they wished to do it on a far grander scale. Granted, I tend to think the people who run Gmail are more honest than that, but if someday the wrong people retired and others took over or what have you, I wonder just how suddenly that could change?
In fact it would be a stupid idea for them to sell any of that data directly to a 3rd party. Instead they package them in user friendly (marketer/advertiser friendly) ways to capitalize. Some of these are shady and I'm not a fan but overall I think this approach is fine.
The problem happens when you sell user data to a 3rd party.
Here's an example: Let's say you start an email newsletter about travel. You get millions of subscribers. Then you start putting ads on your email. Maybe sometimes even send sponsored messages. This is kind of annoying but not "unethical".
On the other hand, the same company could take all the email list and sell it to bunch of travel agencies. Then all the million users who subscribed suddenly start receiving spam emails from these travel agencies. This is unethical because they literally "sold" your email address.
Of course this is more of an extreme example, but the pattern is the same.