Initially I liked your idea a lot. But in the current set up it is a hard sell: You preserve my privacy (I read html mails), but you get my Email address and newsletters I like. Facebook needs a couple of likes and can create a psychological profile of you. Now it is a question of trusting a random guy on the internet to be better and not sell my data to the highest bidder. Maybe open source could address this to some extend. Ideally a gmail or outlook add-on that is doing what you described, with the option to use a proxy. But I personally would probably not pay for that.