What do you mean by private conversations? If you're trying to transmit sensitive information, you don't use a postcard. People are jumping on the wrong bad guy here. "If we can just stop the people who are admitting to tracking us in ways we don't like, we can drive back this menace."
The reality is that if you don't like the idea of people doing this kind of tracking, stopping the people that are publicly admitting to doing it is the least of your concerns.
The reality is that if you don't like the idea of people doing this kind of tracking, stopping the people that are publicly admitting to doing it is the least of your concerns.