TrustRank is a special seo link technique for determining safe sites and increasing the quality scores of sites that provide accurate information. It is a special form of qualification used by Stanford University and Yahoo in the fight against spam. It ensures the quality ranking of all spammy websites specially determined by both Google robots and experts.
Many brands in the web environment use spam techniques to rank higher in search engines due to commercial race. Since each page will be difficult to examine, some reliable private sites are flagged and the link exits from them are given website quality scores.