In August 1991, a Finnish student announced on Usenet that he was developing a free operating system for Intel's 386 processor. That same month, Tim Berners-Lee released the first code for what he called the World Wide Web, also on Usenet. Twenty years later and both projects have taken over the world: one very visibly – the Web – and one almost invisibly: Linux.

The Linux kernel, the low-level core of the free operating system, now drives over 90% of the world's fastest supercomputers, nearly all of the world's stock exchanges, most of the world's embedded devices, and is switched on in 60 000 to 70 000 new Android mobile phones every day.

It powers game consoles, routers, air traffic control systems and thousands of the largest IBM mainframe installations in the world. The movie CGI industry uses Linux-based systems almost exclusively to render special effects.

Linux distributor Red Hat is close to $1 billion in value.