Coin collectors the world over will be celebrating the arrival of commemorative coins announcing that the Firefox Web browser has been downloaded 50 million times since it was launched in November.

Firefox's parent company, Mozilla, has commissioned 50 commemorative coins that will be handed to those people who have done the best job promoting the browser.

The coins are designed by Jamey Boje, a Firefox volunteer.

Firefox has been gaining market from Microsoft's Internet Explorer (IE), perhaps due to fewer security problems, and also due to features such as tabbed browsing, available in Safari but not IE. While IE has 86 per cent of the browser marked according to OneStat, Firefox

Mozilla was set up by Netscape – the company that dominated the Web browser market in the 1990s.