What is the most powerful piece of software you've used today? If you thought Microsoft Word, think again. Odd though this may sound, it's probably Google. Running off a huge 10,000 cluster of computers at Google HQ, it's a mega-database, simultaneously providing near-instant answers to millions of users across the globe. Like much of software we use on a daily basis, it is not even running directly on our machines. It runs on remote servers and we access it courtesy of the web. In a similar vein, many companies are saving money by providing staff with access to their databases through web browsers.

In the last quarter century software has come full-circle. It once ran on huge mainframes which users would access through terminals. The personal computer put software directly on people's desktops and enabled millions of people access to computers for the first time. Now, with the internet, software is increasingly being provided to us across the network again.

Additionally, we may find that the bread-and-butter software we install on our PCs - like the operating system and office software - does not cost as much in the future, in anything. Industry insider Tim O'Reilly says that software is becoming a commodity. There's something in this. It really doesn't matter much which e-mail program or web browser we use because they all understand the standard protocols. Nor does it matter much which operating system we're using. In office software, XML is a threat to Microsoft because it offers an open, industry-standard way of saving information. Even Microsoft has felt obliged to adopt XML (sort of). Attempts to make open-source alternatives to Microsoft Office are getting better.

If software tends to run off servers and doesn't mind what operating system is being used to access it, that poses a big question about what sort of system we need to run on our desktop PCs. The network effect which encouraged the use of Windows is losing its importance. Why pay for Windows to run on the desktop if Linux and a web browser will do the same job?