FlexTrustRank: A New Approach to Link Spam Combating

The quality of search engine service relies on its capability to rank the webpages related to the user query in order of their intrinsic value. PageRank constituted a break-through as a method of webpage evaluation and was in use since then for multiple web search engines. This concept has been subject to attacks by malicious web linkage. As an counteraction, the so-called TrustRank was developed that instead of trusting all webpage developers it trusts only a handful of them that were manually selected. This approach has however a number of deficiencies: (1) it affects mainly the pages close to the manually selected pages, (2) it punishes other worthful webpages, (3) it leaves still a margin of manipulation on webpages with topics distant from those selected manually.