That's not surprising. Look him up in a library card catalog and you'll find lots of books. Some of them might have incorrect information, but at least you get the names of the author and publisher and the publication date. If you look up Thomas Jefferson on Yahoo you'll get links to 97 sites including the Thomas Jefferson Wine and Food Society. But at least Yahoo is a database compiled, in part, by people.
Some search engines sniff out Web data without any regard to the context of the information.
AltaVista comes up with 92,000 references to Thomas Jefferson, including a few that are X-rated. Most are about the sea mammal, but some refer to the male sex organ. You don't even want to know what happens when you enter Barbie or Bambi. In other words, kids don't have to stumble upon pornography to have a bad experience on the Web. Simply being lost or overwhelmed can also make a child uncomfortable and diminish the quality of his or her Internet experience.