AltaVista worked by using Computers to do these 2 parts. computers performed the repetitive organised documents from the Internet.
Yahoo Used human beings instead to capture, identify and describe all the documents. A directory of all pages that were worth visiting was produced. This method proved good when the directory was small. But when the lnternet grew bigger, it became less manageable.
Google came out with the way to manage the huge amount at: information on the Internet. Google used both computers and human beings to do what they are best at doing