Looking at the history of email, it was offered for free, at one point, email giants planned to start charging monthly fee, it never happened. Imagine if you have to pay Google for online searching, it won’t work, nobody will pay for it because it has ‘always’ been free. That’s why you have to admit that whoever invented this so called ‘ad-supported revenue model’ is a genius. On the other hand, Tim Cook also had his point when commenting on ‘ad-supported revenue model’, “you’re not the customer, you’re the product”, basically he’s saying a great customer experience shouldn’t come at the expense of your privacy. So far, it seems that both models work well.