A Google bomb (also referred to as a ‘link bomb’) is Internet slang for a certain kind of attempt to influence the ranking of a given page in results returned by the Google search engine, often with humorous or political intentions. Because of the way that Google’s algorithm works, a page will be ranked higher if the sites that link to that page use consistent anchor text. A Google bomb is created if a large number of sites link to the page in this manner.
Google made changes to its algorithm to prevent such attempts at manipulating a keyword. However, looks like people against Scientology have overcome Google’s attempts to prevent Googlebombing.
If you type in “dangerous cult” into Google, the first result is the Church of Scientology’s official website.