That's fair, I don't know equivalent numbers here either, was just curious. Because if you log in without meaning to, then get nudged to sync, and only get E2E optionally that's a lot of people with pretty bad data protection.
Not saying this as a jab, but it's what I was thinking about in the original post. Fixing that would improve privacy more than FLoC. Not at all a reason not to do FLoC, I love the research, but the priorities seem confusing?