Module suggestion: 'Was this article useful to you?' counter

I just got an idea for a module for Drupal. I have a drupal site where I post articles on various software related problems I've run into and how I solved them, as well as some tips. Currently these are about Ubuntu Linux, Vi and LaTeX. I notice in my statistics I am found pretty often through search engines with terms related to these problems so apparantly people find my page in an attempt to solve their problems.

Because people will not post comments that much (probably because I've got required registration among other things) and I would like some feedback on whether or not the article helped I thought some sort of counter a la amazon reviews like "Was this article useful to you?" Y/N might be nice.

If this does not yet exist in some way I might write it myself and contribute it. Please stop me if this already exists or it's a real stupid idea for some reason ;-)

Thanks,

Karin