I think that there will be ethical issues as long as "your" data is owned by the company collecting it, not you and can be used in any way without your consent.

I think that there will be ethical issues as long as "your" data is owned by the company collecting it, not you and can be used in any way without your consent. I believe that until this relationship is reversed, voluntarily giving your data can never be beneficial. If your data can be collected and traded freely there is a high probability of it reaching well-paying but malicious parties at some point, if even just in a decade when the company goes bankrupt. I'm curious how things like GDPR that attempt to fix this will change the landscape in terms of this.