Linux is believed to have somewhere between 4 and 27 million users, with best estimates towards the upper end of that range. (According to IDG, business Linux usage increased 212% in 1998. Other figures indicate it is roughly doubling yearly.)

The Netcraft web server survey tallies which web servers are used on the Internet. It consistently shows the open-source Apache web server to have over 50% and steadily increasing market share, beating out better-hyped proprietary products like Netscape's and Microsoft's server suites.

The Internet Operating System Counter collects data about operating system usage on the Internet in Europe. It consistently shows Linux is the most popular Internet-connected operating system there.

Indirectly, everybody who sends email or uses the Web is using open-source software all the time. The running gears of the Internet (its mail transports, web servers, and FTP servers) are almost all open source.

This is exactly backwards, as any cryptographer will tell you. Security through obscurity just does not work.

The reason it doesn't work is that security-breakers are a lot more motivated and persistent than good guys (who have lots of other things to worry about). The bad guys will find the holes whether source is open or closed (for a perfect recent example of this see The Tao of Windows Buffer Overflow).

Closed sources do three bad things. One: they create a false sense of security. Two: they mean that the good guys will not find holes and fix them. Three: they make it harder to distribute trustworthy fixes when a hole is revealed.

In fact, open-source operating systems and applications are generally much more security-safe than their closed-source counterparts. When the "Ping o' Death" exploit was revealed in 1997 (for example) Linux had fix patches within hours. Closed-source OSs didn't plug the hole for months.

Alan Cox has written an excellent article on The Risks of Closed Source Computing.

The Open Source Initiative does not have a position on whether ideas can be owned, whether patents are good or bad, or any of the related controversies. We think the economic self-interest arguments for open source are strong enough that nobody needs to go on any moral crusades about it.

Linux is an open-source operating system, and to date the most dramatically successful open-source platform. Linux is very popular in education, Internet service applications, software development shops, and (increasingly) in small businesses. Several successful companies market Linux and Linux applications.

Linux isn't the whole open-source story, however. There are many other open-source operating systems and applications available, including Netscape's Navigator and Communicator client line of Web browsers.

The Open Source Initiative is a marketing program for free software. It's a pitch for "free software" because it works, not because it's the only right thing to do. We're selling freedom on its merits. We realise that many organisations adopt software for technical or financial reasons rather than for its freedom. Many users learn to appreciate freedom through their own experience, rather than by being told about it.

So that it is clear what kind of software we are talking about, we publish standards for open-source licenses. We have created a certification mark, "OSI Certified," to be applied only to software that is distributed under an open-source license that meets criteria set by the Open Source Initiative as representatives of the open software community. We intend this mark to become a widely recognized and valued symbol, clearly indicating that software does, in fact, have the properties that the community has associated with the descriptive term `open source'.