Bahamut, extensions are like mini programs/add-ons that increase the functionality of the browser.
Firefox ships with full functionality as a stand-alone browser but some people prefer to have a little more functionality over the standard offering, that's where the extensions come in.
The best thing about extensions versus all-one-super-mumbo-jumbo browser is that you only download and use extensions that you need so that the browser will not be too bloated to the extent that it takes too much resources to run.
One of the good example of extensions is the mouse gesture. You could live without this feature but people like me would say otherwise.
Another good example of the extension is the "fireFTP". With this extension, you will have a built in (complete but rather simple) FTP client into the Firefox browser. FTP client is not as useful as it used to be nowadays because of P2P progras like Kazaa and BitTorrent but once in a while I do find the need to use a FTP client. *mumble* if only someone would bother to make a BitTorrent client extension... now, that is one very useful extension, IMO.
[ 10-18-2004, 09:15 AM: Message edited by: Paladin2000 ]