Revealing the relationship network behind link spam

Accessing the large volume of information that is available on the Web is more important than ever before. Search engines are the primary means to help users find the content they need. To suggest the most closely related and the most popular Web pages for a user´s query, search engines assign a ranking to each Web page, which typically increases with the number and ranking of other Web sites that link to this page. However, link spammers have developed several techniques to exploit this algorithm and improve the ranking of their Web pages. These techniques are commonly based on underground forums for collaborative link exchange; building a relationship network among spammers to favor their Web pages in search engine results. In this study, we provide a systematic analysis of the spam link exchange performed through 15 Search Engine Optimization (SEO) forums. We design a system, which is able to capture the activity of link spammers in SEO forums, identify spam link exchange, and visualize the link spam ecosystem. The outcomes of this study shed light on a different aspect of link spamming that is the collaboration among spammers.