IMO we are having the wrong conversation. We should be debating whether or not any user data should ever be allowed to be shared with third parties. We could live without it.
<a href="https://hubski.com//pub/405379">Discuss this on Hubski.</a>
Agreed, but unfortunately we have to be more proactive in not giving that data to others to begin with.
We never will, and it will always remain difficult to measure at best.