Obligatory cynical comment: It won't work. For the simple reason that if it is successful commerce will find a way in. A large enough group of people will always be marketed to in one way or another. And once that happens the budgets will follow and before you know it you are in the next phase of centralization. I would not know of a way to side-step this effect, unless the plan is to create something that only few people will ever use.

The internet already is for everyone - everyone with an internet connection, that is - and that is precisely the problem. So unless you are willing to drastically limit the influx of users sooner or later there will be a swing back to centralization, for instance by companies that require you to give up some of your rights in exchange for hosting your data. And then you are more or less back to today, only with lots of little data-stores that can be merged at will by whoever controls the storage facility after you cough up your keys in return for something shiny.