TrustRank

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TrustRank is a link analysis technique for semi-automatically separating useful webpages from spam. (Gyöngyi et al. 2004)

Many Web spam pages are created only with the intention of misleading search engines. These pages, chiefly created for commercial reasons, use various techniques to achieve higher-than-deserved rankings on the search engines' result pages. While human experts can easily identify spam, it is too expensive to evaluate manually a large number of pages.

One popular method for improving rankings is to increase artificially the perceived importance of a document through complex linking schemes. Google's PageRank and similar methods for determining the relative importance of Web documents have been subjected to manipulation.

The TrustRank method calls for selecting a small set of seed pages to be evaluated by an expert. Once the reputable seed pages are manually identified, a crawl extending outward from the seed set seeks out similarly reliable and trustworthy pages. TrustRank's reliability diminishes as documents become further removed from the seed set.

The researchers who proposed the TrustRank methodology have continued to refine their work by evaluating related topics, such as measuring spam mass.

[edit] Bibliography

Zoltán Gyöngyi, Hector Garcia-Molina, Jan Pedersen, "Combating Web Spam with TrustRank", Proceedings of the International Conference on Very Large Data Bases 30:576, 2004.