Link Bombing
More commonly known as Google Bombing, due to the prevailance of the Google search engine, link bombing causes a webpage to rank in search engine results for an otherwise unexpected search phrase.
Link bombing is often carried out for amusement, as demonstrated by the well known 'miserable failure' link bomb. In this case the webpages of George Bush, and Michael Moore, appeared in the number one and two result spots when using the search term 'miserable failure'.
Link bombing is also used for commercial purposes by some, attempting to push competitors websites and negative news stories out of the top listings.