Not true -- advertising profiles are vastly more valuable when based on a lifetime of data.

> also by having ability to enable/disable access to your data, you have the power of who gets what

But realistically, when are you ever going to disable access? If you want people to be able to read your replies no matter what social network they're using, you're going to make those replies available to every social network.

> and for which purpose also reselling of your data should become illegal to start with

This is my point. The solution here is legal, not technological. Personal data storage doesn't change anything legally, and changing the law would prevent reselling even if you didn't have personal data storage.

It seems important not to confuse the two, in order not to give people false hopes.