I agree that data can be in different levels. The first thing I think should happen is informing the people, say if you send me an PM about a medical issue you

I agree that data can be in different levels. The first thing I think should happen is informing the people, say if you send me an PM about a medical issue you have you should be informed that your message will be analyzed and a hidden profile of you will be updated and then sold. At least if you want to trade your data you should be able to read a clear contract on what you trade and what you get in return.