It doesn't matter if you have the right to see who has your information, or even to get a copy or correct it, if you can't force them to delete it too. And, as we know, just asking a company to delete some data from their records, especially if that data is valuable to them, is not a directive that is going to be followed with haste and efficiency. This is why we need disposable identity information: contact details that self-destruct when I say so, no matter what you do as a company to hold onto them. It is the only way to true privacy without going for witness protection.
The problem with setting up such identity misdirection is that you have to trust someone. Your bank is going to manage your disposable credit cards by charging your real one. Your ISP or some online service is going to deal with your disposable email addresses by forwarding to your real address. Your phone company will manage all your disposable phone numbers by forwarding them to your real one. And the temptation to sell your direct contact details to their advertising partners will always be too great to resist. The buck stops somewhere, and it's always just short of actual control by you.
Mokalus of Borg
PS - I actually think about this a lot.
PPS - And I guess I post about it a fair bit too.