'Google Bomb' an Enemy

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.
Step 1: Plan Your Assault
You'll need a lot of friends who can be convinced to cooperate. The number of links you need depends on a number of factors, including the PageRank of the sites the phrase is posted on as well as the precise phraseology.
Alternatively, you can do all the linking yourself, but you would need at least a few hundred links on separate domains to get the desired result.
Typically, the victim is someone you and a bunch of other people dislike. The more high-profile the target, the better your chances of being seen and making your point.

Step 2: Generate a Whole Lotta Links
The more highly-ranked links search engines detect, the greater rank the chosen site will receive. Typical links include the URL of the target site, with the key phrase comprising the anchor text of the link. A link's anchor text is the words that appear between the and the closing tag in a link.

Tip: The more obscure the linked phrase, the better. If the phrase you choose is a popular one, you may need more links than an obscure phrase.
The total number of links depends on a lot of factors, but think in terms of hundreds or thousands, not millions. For example, the hacker radio show Off The Hook successfully Google bombed themselves with the search term "blank expressions." They peaked as the 6th-ranked site for that phrase with a total of about 350 links.

Step 3: Tell Everyone
What's the use of link bombing if no one notices? After the bomb takes hold, publicize it so ordinary citizens learn all about your move.

Tips & Tricks
In January 2007, it was announced that google would be taking steps to limit the effectiveness of google bombing. It's subsequent algorithm tweak rendered most bombs ineffective. Rather than eliminate them altogether, Google directed search queries to discussion pages describing the bomb and Google's reasons for defusing them. Furthermore, Google is known for manually altering PageRank scores for various reasons, including succumbing to political pressure. Many Google bombs have been suppressed for public relations reasons.
Yahoo, AltaVista and other search engines have not announced any similar measures, so many older bombs that no longer work with Google still work with these other engines.
Also, it is possible to Google bomb for commercial or self-promotional purposes. Commercial link bombing, also known as "spamdexing," involves driving traffic to sites by the massive creation of links via bots, usually targeting the comment fields of blog posts.