-Types of Search Queries:

Andrei Broder authored A Taxonomy of Web Search [PDF], which notes that most searches fall into the following 3 categories:
Informational - seeking static information about a topic
Transactional - shopping at, downloading from, or otherwise interacting with the result
Navigational - send me to a specific URL
Improve Your Searching Skills:
Want to become a better searcher? Most large scale search engines offer:
Advanced search pages which help searchers refine their queries to request files which are newer or older, local or in nature, from specific domains, published in specific formats, or other ways of refining search, for example the ~ character means related to Google.
Vertical search databases which may help structure the information index or limit the search index to a more trusted or better structured collection of sources, documents, and information.
Nancy Blachman's Google Guide offers searchers free Google search tips, and Greg R.Notess's Search Engine Showdown offers a search engine features chart.
There are also many popular smaller vertical search services. For example, Del.icio.us allows you to search URLs that users have bookmarked, and Technorati allows you to search blogs.
World Wide Web Wanderer:
Soon the web's first robot came. In June 1993 Matthew Gray introduced the World Wide Web Wanderer. He initially wanted to measure the growth of the web and created this bot to count active web servers. He soon upgraded the bot to capture actual URL's. His database became knows as the Wandex.
The Wanderer was as much of a problem as it was a solution because it caused system lag by accessing the same page hundreds of times a day. It did not take long for him to fix this software, but people started to question the value of bots.