For anybody not a secret that for references to "bad" sites of Google reduces a site, superimposes various penalty, in special cases banned. In a word referring to poor-quality sites we spoil to itself trust. Whether Then thought will be true that referring on authoritative, trust we will improve sites to ourselves trust. For example, on the site of university I will refer on any.gov or.edu I Invite all to come up with the ideas, observations, suppositions!