Now, although Search can't be held directly responsible for the material it indexes, for the material it gives easy access to, as any parent and law enforcement officer knows, it certainly makes finding and accessing undesirable information a lot easier.
In the real world (for geeks define:real world) finding undesirable information can be a lot harder than you would think.
From how to make a bomb (includes easy links to related searches like how to make a bomb with household items and home made bombs) to how to commit suicide (user-friendly links to the related searches painless ways to commit suicide and methods of suicide) and from what happened in Kashgar China to US military equipment in Iraq, some questions, depending on where and when they are asked by whom, can raise red flags.
Some questions you, parents, or government organizations would rather not see so easily answered.
It's true that it's the anonymous, large-scale nature of the World Wide Web that makes the dissemination of this information terribly simple. But it's search, and only search, that makes it useful, findable, accessible.
Without Search you'd find yourself at the equivalent of walking into a bar, asking for an illegal passport, some cocaine and an illegal gun: it doesn't work that way.
Without Search you'd need someone who knows someone who knows someone. And depending on the what and the someone's, you need credibility, need to be able to be trusted, before you're introduced and moved on towards the next stage.
As media companies are starting to look towards ISP's to filter illegal file sharing, so law enforcement agencies will increasingly look to Search: the door through which easy access can be gained can be easily closed, allowing only certain information in and through, condemning the rest to obscurity and through obscurity to exposure by forcing those interested out into the open.
In essence, for any party concerned, be it a parent, an employer or the law, there is no need to monitor websites visited, emails sent, instant messages made; one only needs to monitor Search to follow and understand the direction and development of someone's interests.