sentences:  Adversarial IR includes the study of methods to detect, isolate, and defeat such manipulation.On the Web, the predominant form of such manipulation is search engine spamming (also known as spamdexing), which involves employing various techniques to disrupt the activity of web search engines, usually for financial gain.Examples of spamdexing are link-bombing, comment or referrer spam, spam blogs (splogs), malicious tagging.