black. I remeber it is a way to do a lot of backlinks with keyword to a page which not has relative with the keyword or contain the keyword. But because of the anchor text, the page can get a good rank in google.
That Wiki was quiet interesting. I know what is Google Bomb today with examples(George Bush) in wikipedia was really interesting.
For example, if a user registers many domains and all of them link to a main site with the text "... is a living legend" then searching for "living legend" on Google will return the main site higher in the ranking, even if the phrase "living legend" doesn't appear on the main site. A common means of exploiting this is through weblogs, where although the entry may disappear from the main page quickly, the short-term effects of a link can dramatically affect the ranking of a given site. Empirical results indicate that it does not take a large number of websites to achieve a Googlebomb. The effect has been achieved with only a handful of dedicated weblogs.
It happens when a lot of sites give back links to a specific site with a specific keyword.It's completely black hat.