US v Gates: Why it matters to you

If you've recently bought a PC, or are getting one for Christmas, you'll quickly see what the legal row has been about. Click the icon saying "Browse the Internet" and you will find yourself at Microsoft's home page.

Why? Because that "Browse" program (actually called Internet Explorer, or IE) is written by Bill Gates's company. And Microsoft told the PC- maker that unless it installed IE, then it couldn't have Windows95 - the "operating system", without which a PC is of little use to the average person. Obviously, the PC-maker said yes.

But why has it taken you to Microsoft's home page? Because that's a "default" setting, built in by the company so it can show potential advertisers that lots of people visit its site. You can change that default in less than a minute - but Microsoft would rather you didn't.

Any software has "defaults" - the settings of parts of the program as it starts up. In a browser, a key default is the "home page", where the program automatically takes you when it starts up. If lots of people visit your home page simply because they start the program, you can charge more to advertisers who buy space there. Many people never realise that they can change the default.

For almost two years Microsoft has tried to use the dominance of Windows95 to jump-start the market share of IE. Its chief rival, which was on the scene rather earlier, is Navigator, from Netscape Corporation of Mountain View, California. Netscape's 18-month lead over Microsoft in producing a browser gave it an 80 per cent share of the small, but fast-growing market.

Navigator's default home page is the Netscape Web site; that of IE, the Microsoft site. So far, so fair.

But peoples' tendency to stick with defaults also extends to their software. If your machine already has a browser, why get another? So Microsoft told PC manufacturers: include IE as standard software on your machine, or you can't have Windows95. Netscape's market share began falling dramatically, and the number of "hits" on Microsoft's home page began rocketing. Netscape cried foul. Microsoft responded that IE was "part of the operating system". This seemed odd, since it doesn't sell or market any other part of its operating system separately. Microsoft's argument looked thin; its tactics, vicious. The decision means that some equality will be restored.