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
What's the difference between corrections and criticism? Did you get any that changed the way you do things?
Corrections are things like 'you have a typo in X' or 'your CSS is broken' or 'you forget this'. Criticism is closer to, to paraphrase one, 'X is the worst thing on your site, is incredibly embarrassing, and you should feel bad for ever writing it.'