One more reason to make sure your email account is not compromised in any way. I have many emails associated with my 'profile'. If one of those is compromised somebody could potentially request all of my data.

Requests for information should only be fulfilled with a notarized identification verification. The potential for security breaches here is massive.

Yes, this. Collecting my data would bother me somewhat less if it weren't also so freely distributed.

I don't have an account with Quantcast. That's the whole point.