EMPIRES rise and fall swiftly on the internet. Google’s Chrome browser, which celebrates its fifth birthday next month, has captured much of the territory of older browsers and is now responsible for about 43% of all the web traffic generated by the world’s desktop computers. When Chrome was launched the dominant browser was Microsoft’s Internet Explorer (IE), with a 68% share—it is now down to just 25%.

It is only 20 years since Mosaic, the first browser capable of combining words and images in a single page, was made available. Some of its developers went on to launch Netscape, an improved version, in 1994, just as the internet was taking off. But Netscape’s dominance quickly crumbled after Microsoft started bundling IE with its Windows operating system. IE and Microsoft’s other software became so prevalent that in 2000 an American court briefly contemplated breaking the company into two.