Firefox and Internet Explorer are two of the most popular web browsers currently in use. A report on browser statistics from w3schools.com shows that in August of 2009, Firefox made up 47.4 percent of user's browsers. Internet Explorer versions 6, 7 and 8 totaled 13.6 percent, 15.1 percent and 10.6 percent respectively.
The difference is the software itself. Internet Explorer is the default web browser with Microsoft Windows operating system, much like Safari is the default web browser for Macintosh OS. Firefox, however, does not come with either system. Users must visit Mozilla's website to download the browser before they can use it.
These small differences aside, the two are the same in that they are applications used to browse the Internet.