The technology of link analysis used for a semi-automatic separation useful links from spam. Many of spam pages are created with a single intention – to confuse the search systems. Such pages are basically created for commercial purposes. They use different technologies to reach an undeserving position in SERP. Though people can easily distinguish spam from useful sites, it is too expensive to verify big amounts of pages. One of the most popular methods of reaching top positions is an artificial boost of the “importance” of document with help of complex link schemes. For example, Google’s PageRank and other methods of definition of relevant webpage authoritativeness are objects of such manipulations. The TrustRank technology selects a small amount of pages verified by an expert. As soon as the quality of these pages is confirmed, the search starts. The robot searches for reliable and quality pages similar to the primary set of trusted documents.