Blind trust in such a simply verifiable case is quite naive.
You can easily open up the front page of HN as a logged in user and see that it contains information about which storeies you've voted for and which you've flagged. On top of that, you can click "hide" to hide stories. These will only be hidden for your specific account, not for every person who loads the front page.
What's more, the go-to call-to-action by HN admins during really popular stories is to have people log out, because logged in users don't get cached results. Have a look at the comment by HN admin dang on the Trump winning story. [1] The key part being "please log out to read HN today, unless you want to comment. Then we can serve you from cache".
Exactly. It's the difference between "Look up the first 100 people in this phone book not named Justin" and "Look up the 100 Justins that come first alphabetically across these 100 phone books"
As far as I know hide doesn't change the order, it just skips some results. This is a far simpler problem than merging multiple sources of information into one result.
