Directories (A directory is a database collected by humans and categorized ... in an outline format)
Pros: sites are recommended by humans - their data is reviewed, evaluated and categorized by humans - most data is gem quality - junk is discarded - data is much better organized - searches recover less junk
Cons: much smaller database than for Search Engines - does not search the WWW - only sites that are submitted are analyzed - many gems aren't found - very few jewels
Search Engines (A search engine, crawler, havester, robot, searcher, spider, wanderer, or worm is a computer program that automatically searches Internet sites and collects their data)
Pros: a more complete search - extremely large database - collects data from millions of sites - collects tons of gems, including many jewels
Cons: collects tons of junk - finds completely inappropriate and poor "matches" --- searching for ROCK (a stone) would also return ROCK HUDSON, ROCK AND ROLL, ROCKET, RADIO HALL ROCKETTE, ROCKING CHAIR, ROLLING ROCK beer, ROCK OF AGES song, ROCK OF AGES CEMETARY, etc. --- user must structure request to limit search to pertinent data
Meta-Searchers (A meta-searcher is a program that uses more than one search engine simultaneously)
Pros: more thorough than any one Search Engine
Cons: slower than using just one engine
Multiple Searchers (A multiple searcher is a collection of search engines on one page - the user usually selects which one to use)
Pros: convenience of having multiple searchers on same page
Cons: not as efficient as Meta-Searchers, since only one engine is working at a time