I-World - Internet Services and Information Management
Searching the Internet
Types of Searching Sites
Meta Sites: These search using some combination of other engines and indices.
Search Engines, Spiders (Arachnids), Robots: These have software agents which go out and catalog every page they find, unless it is excluded by a norobots file. Pages show up eventually, whether or not they are submitted.
Indices, Directories: These catalog web sites and pages which are submitted for listing and/or discovered by the librarians.
The Spiders Apprentice is one of the most definitive sources of information available on searching. They rank the various seach sites as well.
Capital Crest has a long list of calculators of various kinds.