But the data is kind of crappy. The same user coming back in two different days is considered two unique users.

In a way that's an important feature. I don't want to (be able to) track individual users, and I don't think I have to.

I don't have to tailor ads to the visitor or something, I just want accurate enough stats in aggregate.

Great find. Best statistic on HN userbase and "HN hug" I've ever seen.