What is TrustRank?
TrustRank is an algorithm that Yahoo and Google use to differentiate good and bad (spam) websites.
The TrustRank algorithm works by analyzing the backlink profile of a site. It begins with a human expert manually entering a few trustworthy sites into the algorithm.
Once done, the TrustRank algorithm begins to follow the backlinks the trustworthy sites link to. These sites are also considered trustworthy, as are the sites they link to, and it goes on like that.
The TrustRank algorithm is based on the logic that trustworthy sites will only link to other trustworthy sites.