Yahoo’s Link-Based Spam Detection Patent Application

In an effort to curb spam, TrustRank has been used as one of the factors in establishing rankings in search engines like Big G.

Now, Yahoo is joining in the game by using domain “Trust” as a ranking factor.

From the latest patent abstract by Yahoo:

A computer implemented method of ranking search hits in a search result set. The computer-implemented method includes receiving a query from a user and generating a list of hits related to the query, where each of the hits has a relevance to the query, where the hits have one or more boosting linked documents pointing to the hits, and where the boosting linked documents affect the relevance of the hits to the query. The method associates a metric to each of at least a subset of the hits, the metric being representative of the number of boosting linked documents that point to each of at least a subset of the hits and which artificially inflate the relevance of the hits. The method then compares the metric, which is representative of the size of a spam farm pointing to the hit, with a threshold value, processes the list of hits to form a modified list based in part on the comparison, and transmits the modified list to the user.

The patent provides some insight into the way it would identifying spam pages from search results, in conjunction with pagerank. The system sorts reputable pages from spam pages by using combining with input from humans reviewers who manually identify these reputable seed pages.

While link “trustability” acts as a fairly good indicator of site quality overall, it is still flawed as shown in the case of Expedia subdomains.