Single and/or Multiple Search Engines?

What are they?

Don't know, never heard of them. Perhaps there's another name for them?

soz dave, you're wrong, multi-search engines are quite popular... theres a lot i could wright and i really dont have time, so http://www.philb.com/msengine.htm should tell you more, i read over it briefly and its all right up to "Comparison of the search engines" which is where i stopped reading, it should be a reliable sight though, the first bit was fine...

 

single search engines are just 'normal' examples are google, askjeves, alta vista, excite & lycos (just checked, those are the main ones)

I've never heard them called that before, but never mind.

 

There's nothing particularly special, they just use multiple search engines to gather their results.