Notices of new and updated software for Linux and other free OS's. Please send additions to this list to the FAQ maintainer. Linux is freely available, and no one is required to register with any central authority, so it is difficult to know. Several businesses survive solely on selling and supporting Linux. Linux news groups are some of the most heavily read on Usenet.
Accurate numbers are hard to come by, but the number is almost certainly in the millions.
However, people can register as Linux users at the Linux Counter project, which has been in existence since 1993. The current count is posted monthly to comp.os.linux.misc , and is always available from the Web site. In 1999, International Data Corporation released its first commercial forecast of Linux sales. Discussions like these frequently occur on Usenet. Most often they're flame bait.