Random question: what's a spider?

[chellrose]

I was just on the main Forums page, and happened to scroll down all the way, and saw this:
Currently Active Users (http://ubuntuforums.org/online.php): 6827 (337 members and 6447 guests and 43 Spiders)

What's a Spider? (In the context of UF, I mean.)

[pi3.1415926535...]

At the very end of the list, one can notice names such as Google, Yahoo!, MSNBot etc. Each of these has a number displayed after like this; (x). The number totals the total number of spiders, so I would assume that they are computers under the operation of these companies collecting information of some kind.

[Version Dependency]

They "spider" the web. They are automated programs that methodically go from web page to web page collecting information...to be used in search engine results, to ensure you get the most relevant results.

[Quadunit404]

Something that's quite small and fits into most overhead compartments A tiny script that indexes pages for a search engine.

[chellrose]

Oh, ok! Thanks. Slightly less confused now. :D