In 2011, I added an anonymous feedback form to
gwern.net
. It has worked well (116 entries) and justified the time it took to set up because it encourages people to correct various problems or tip me off on things. If you have a site, maybe you should add one too.
For the full writeup, see http://www.gwern.net/About#anonymous-feedback
On a not very related note, what were your conclusions from the Hacker News posting experiment? The articles seemed to do quite well.
I haven't finished yet. I seemed to have been hit with a massive submission penalty which makes me unable to reach the main page anymore, though, so I will probably stop soon.