Directories are NOT Search Engines. They are directories, similar to phonebooks, that have been categorizing the Internet for eld. Of the peak striking directories on the Internet the top one is DMOZ but location are also more than a few 200 poorer identified ones.
Some of the Search Engines use the encyclopaedia table of contents in their Search Results. Look Smart is one, AOL is different. Yahoo utilized to use the DMOZ key as segment of its activity results. Many lesser known, but active, look into engines use directories as the basis for providing information for all of their searches.