You don't need to be sceptical about my account :) It has been registered with Hackernews for >1 year. Many YC alumni can confirm me being real and being not Dominik (founder of refind). I know him personally, I have been a happy user of refind and when I learned there was a chance to push it on hackernews I did.

How does the filtering work? I have to admit that I have not 'gotten' Refind so far but that might change with some help!

The filtering is basically done by the people you follow. They add what they find interesting and that is a pre-selection.

Most users seems to add all links from their tweets. Maybe that will change!

Not in my experience. But as I have mentioned in my own top-level comment, I have been fairly diligent about unfollowing the people that produced noise in the stream.