UCC's Tips for Searching The Web
Those Dark Hiding Places: The Invisible Web Revealed--librarian Robert J. Lackie provides a concise guide to web directories, the invisible web (searchable sites and databases not indexed by general search engines), and different types of search engines.
Search the Internet: A graduated approach in 4 steps from UC Berkeley Library. Includes links to search engines, categories of search tools, and strategies for finding information and sites.
Search Engine Showdown compares features and size of search engines, offers search strategies, outlines strengths and weakness of search services, provides news and updates, and more.
Search Engine Watch One of the best places to learn about search engines, their size, their partnerships, and lots more. For example, take a look at these two pages of information:
Search Engine Sizes provides comparisons, charts, and more to demonstrate differences between search engines.
Web Directory Sizes presents a handy chart comparing sizes and resources of popular subject directories