Meta-Search Engines
In addition to these large indexes are meta-searchers, which take relatively simple input and search many indexes at once.
Meta-Search Engines allow you to search several keyword search tools (including some subject directories) with a single search command. These convenient tools translate your search into syntax other search tools understand, and retrieve a composite result as if you had searched all of the other databases individually. Their use is limited to fairly simple and straightforward searches.
In a meta-search engine, you submit keywords in its search box, and it transmits your search simultaneously to most of the popular search engines and their databases of web pages. Within a few seconds, you get back a compilation of results containing matching sites from all of the search engines queried. This can save you a lot of time and provide an overview of the kinds of documents "out there" matching any term, phrase-in-quotes, or set of terms and phrases. It may result in locating exactly what you want, especially if you are searching a unique term or phrase.
Meta-search engines do not own any database of web-pages; they
use and deliver the databases and searching programs of each of
the popular, individual search tools they query. Meta-search
engines act as intelligent middle-agents to pass your search
through, gather the responses from the individual search tools
they query, and then give you a more unified report of results
from many different resources.
NOT a cure-all: Only a SHORTCUT for SOME searches.
If you submit a complex search that one or more of the individual search tools queried does not "understand," you will get garbled or zero results from that tool. However, you will usually get results from some other tool that supports your fancy search strategy. Therefore, meta-search engines do NOT eliminate the need to learn how to search skillfully at least a few general web searching tools (such as AltaVista, Infoseek, and Northern Light). The better you know how they each work, the better you can judge the reliability of search results from meta-searches sent to them.
So. . . Let's get on with it!!!