Ask
Works by having you pose a question in plane English. Cha Cha
Works with human assistants. Google
Works by ranking sites by popularity based on links to it. Northernlight
Works by categorizing sites into groups and folders. Search
List of sites that allows you to search for anything.
Database Search Engines
Vertical Portal Search Engines (Vortals)
Visual Search Engines
Work by searching for sites that post their information graphically.
