"Google bombing involves manipulating search engines' contextual search methodologies to cause a certain search phrase to point to an unexpected page, usually for comedic or satirical purposes. A recent example of a Google bomb happened in January 2008, when the search phrase "dangerous cult" returned the Chuch of Scientology home page as the top search result.
Google bombing -- also known by the more generic term "link bombing" -- works with any search engine using a relevancy algorithm similar to Google's. For example, run a search for "miserable failure" in Yahoo Search. You'll see prominent links to President George W. Bush's biography at whitehouse.gov at or near the top of the list.
The heart of the system is Google's PageRank algorithm, as well as equivalent competing technologies. The PageRank system assigns a numeric score of 0-10 for each page on the web. Google derives a page's ranking from the PageRank scores of all other pages that link to it.
The key to Google bombing is to generate outgoing links to your target from highly-ranked sites. Get enough highly-ranked sites pointing to your target using the same phrase, and you'll push the target site to the top of the list of search results one sees when entering that mischievous phrase.
Here's how to do it."