What I have never understood is why google has put so much concentration on punishing the Websites that receive web spam. Why not balance it and punish the sites that don't prevent it. Punishing them sites will firstly de-value the link + push webmasters to actually do something on the other end. Sometimes it is out of the site owners control because they cannot prevent that link from being created. The google updates right now encourage negative SEO because that webmaster has no control of that link creation. If you start punishing the people who have control and are able to prevent spam then it makes them focus on being better at moderating that and allowing more relevant links from blog comments and such.