From a long article at the NYTimes, detailing the shady characters contacted.
The businesses that say they can remove the libelous posts are sometimes owned by the same business owners hosting the posts. Other times it's arms-length--the removal service pays to advertise on the libel-hosting site and pays the site to remove the libel. And paying a removal service might just tell them that if they repost the libel somewhere, they can be confident you'll pay more to take it down. It all works because Google and Bing highly promote the sites in search results:
For about one-third of the people, the nasty posts appeared on the first pages of their results. For more than half, the gripe sites showed up at the top of their image results.
Sometimes search engines go a step further than simply listing links; they display what they consider the most relevant phrases about whatever you’re searching for.
One woman in Ohio was the subject of so many negative posts that Bing declared in bold at the top of her search results that she “is a liar and a cheater” — the same way it states that Barack Obama was the 44th president of the United States. For roughly 500 of the 6,000 people we searched for, Google suggested adding the phrase “cheater” to a search of their names.
There is some hope of getting such results removed:
There is another way to lessen the posts’ impact. In certain circumstances, Google will remove harmful content from individuals’ search results, including links to “sites with exploitative removal practices.” If a site charges to remove posts, you can ask Google not to list it.
Google didn’t advertise this policy widely, and few victims of online slander seem aware that it’s an option. That’s in part because when you Google ways to clean up your search results, Google’s solution is buried under ads for reputation-management services like RepZe.
Other people who have used Google’s form reported similar experiences: It mostly works, but is less effective for images. And if you have an attacker who won’t stop writing posts about you, it’s almost useless.