Web spam pages use various techniques to achieve higher-than-deserved rankings in a search engine’s results.

Google recently registered -TrustRank as a Trademark.

A Technical Report titled Combating Web Spam with TrustRank submitted in Stanford University delves deeper into what exactly a TrustRank is? The Report was submitted by Zolt´an Gy¨ongyi and Hector Garcia-Molina from Stanford University and Jan Pedersen from Yahoo! Inc..

The Technical Report in a PDF format is also available.

According to the Report, to combat Web Spam (hyperlinked pages on the World Wide Web that are created with the intention of misleading search engines.), the TrustRank Algorithm evaluates every page against a set of Seed pages.

Seed pages are good pages selected by Human experts which are belived to be reputable, meaning these are most relevant to the searched keyword. Once reputable seed pages are identifed, these are used as a basis to discover other similar pages on the WWW.

In selecting seed pages, preference is given to pages from which we can reach many other pages. In other words, select seed pages based on the number of outbound links.

This is a Inverse PageRank algorithm as in PageRank algorithm, seed pages are selected based on the number of inbound links.

Since the pulled search result pages would be evaluated against seed pages, the results would be much more relevant and will have minimal spam pages.

Search engine experts are interpreting this as an important move by Google to combat Web Spam and in turn improve the search results.