I think that this kind of business model hides an threat unless anonymous payments are provided: you will completely loose your privacy as everything you read is now connected to your more or less real identity and actually nothing prevents them to serve you the ads, especially because you are now identified better than before.

I think this is also the reason why Apple installed the ad-blocker - they want to enter into this market and grow it as it appears that ad-based business model is not working for them.