If you search Google, Bing, or Yahoo for information about the massive BP oil spill in the Gulf of Mexico, there's a very good chance the top result will be a BP site explaining what the company is doing to mitigate the disaster. Coincidence? Hardly. BP is essentially renting oil-related search words and phrases to make sure search engine users see their pages first. (Watch one fan's parody of a "BP" Google search.) Here's a look at what BP's up to:

Why is BP buying search terms?

According to BP, ensuring that its own links are at the top of Google, Bing, and Yahoo's search results will "make it easier for people to find key links to information on filing claims, reporting oil on the beach, and signing up to volunteer," as well as learn about BP's efforts to fix the spill. Though it's hardly unprecedented to purchase search terms, some critics characterize BP's efforts as a PR offensive to influence public opinion and help salvage the company's besmirched image.

What terms is it buying?

BP acknowledges paying for "oil spill," and neutral phrases like "spill," "gulf oil," "offshore oil," "Louisiana coast spill," and "oil cleanup" all return search results with BP's sponsored link at the very top. BP's also apparently paying for "BP disaster," but not "gulf disaster" or "oil disaster."

How much is BP paying for them?

Google sells sponsored links, which are really a form of advertising, to the highest bidder. New York marketing analyst Scott Slatin, who specializes in search engines, estimates that BP is paying Google at least $7,500 a day to "own the top positions" for related search terms, plus another $3,000 a day to cover Bing and Yahoo.

Has anyone else done this before?

Certainly. Political campaigns — notably John McCain's — have paid to sponsor keywords before, and some companies have sponsored links, usually through a nonprofit or lobbying outfit, to buy influence on certain topical political issues, like health care. But this is one of the more ambitious campaigns to combat a corporate PR nightmare — Toyota, for instance, didn't rent the phrase "Toyota brakes" earlier this year.

Is this a good idea, business-wise?

"From BP's perspective it's a brilliant move," says Motivity Marketing CEO Kevin Ryan. "If they're not buying that link that goes back to their message, they're kind of leaving the universe to kind of decide for itself." Slatin concurs that it's a "very effective" PR tactic.

How about ethically?

"That's another question," says Ryan. Louisiana Gov. Bobby Jindal (R) and President Obama both criticized BP for spending millions on PR that it could give to Gulf residents harmed by the oil. And BP's also using its deep pockets to elbow out "news and opinion sites that would normally buy at least one of these terms" — especially less-affluent nonprofits, says Jacqueline Leo in The Fiscal Times. "Oil money, as slippery as it may be, talks louder than most."

Sources: ABC News, DaniWeb, Think Progress, The Fiscal Times, AP