I just read this Electronics SE answer. I found the explanation very clear and interesting, but I don't want to create an account on that site. So, I clicked Yes by "Was this post useful to you?"
Who will get that feedback?
Some statistics are available to 10k users in the tools section, via http://stackoverflow.com/tools/post-feedback
These pages shows some general statistics on the feedback (like feedback/score correlation), and there are tabs that list the most over/under-rated posts, as well as the most and least helpful posts.
Moderators probably have finer-grained information, and obviously Stack Exchange staff more so.
Looks like this on Stack Overflow:
The feedback is recorded in a page that is visible to 10k users and moderators on http://electronics.stackexchange.com/tools/post-feedback, in the case of the site you are referring.
The page reports some statistics about the anonymous feedback, and makes a comparison between anonymous feedback, and the votes given to the same posts.
This is how the top of that page appears on English Language & Usage.
The same information is visible to moderators, who don't get more data. This is what I see on Drupal Answers, where I am a moderator.
Even the rest of the page is not different, if I compare what I see in a site where I am a 20K user with what I see on Drupal Answers, I don't see any difference.