[citation][nom]sykozis[/nom]Microsoft didn't buy IE. IE was originally developed by MS using portions of the Mosaic codebase (open source). BTW, Safari, Chrome and FF are all "stand-alone" browsers. None of them specifically require additional software to run.[/citation]
Bzzz. Wrong! (pasted) The first version of Internet Explorer made its debut on 16 August 1995. It was a reworked version of Spyglass Mosaic, which Microsoft had licensed, like many other companies initiating browser development, from Spyglass Inc. MS has paid over $8million to Spyglass. For the most part, they bought it - worked on it a bit, stuck on the MS logo and called it their own. Its no big deal... its how MS generally operates. (MS-DOS, MS-Word, etc). IE3 was their first own browser and is when I went to IE. *IF* MS was using Open Source - they wouldn't have paid a dime for it, eh?
IE has been offered as standalone as well (Mac version). Opera is stand-alone.