A Google bomb is Internet lingo a kind of attempt to influence the ranking of a given page in results returned by the Google search engine, It is closely related to spamdexing, the practice of intentionally modifying HTML pages to increase the chance of their being placed close to the beginning of search engine results, or to influence the category to which the page is assigned in a misleading or deceitful manner.

Now see what googleblogger write about defusing the googlebomb;
The Google blogger writes: ‘By improving our analysis of the link structure of the web, Google has begun minimizing the impact of many Googlebombs. Now we will typically return commentary, discussions, and articles about the Googlebombs instead.’”