Just how much open source software are people using?  Getting hard numbers about open source usage is one of those tough-to-crack problems that doesn't seem to have a definitive solution -- partly because of the nature of open source itself.  Self-reporting seems to be about the only way to get any numbers at all, unreliable and biased as that may be.  But if self-reporting open source usage is made as easy as a couple of mouse clicks, why not do it?

That's at least part of the impetus behind the Open Source Census, a project sponsored by (among others) open source vendor OpenLogic.  The idea is to have users perform scans of their systems and submit data about what open source applications and packages are in use, and complement that with package-fingerprint information submitted by the creators of open source software.  Information sent back to the OSC is anonymized as heavily as possible, to keep down the amount of proprietary information that might be transmitted.  Reports derived from the submitted data will be aggregated and analyzed quarterly.

The project has just barely kicked off, so the statistics collected so far are a little thin.  Many of the usual open-source suspects are present in the census, though -- applications like Firefox and OpenOffice.org, as well as libraries and languages like zlib, OpenSSL, and Perl.  They also collect stats about which Linux distributions are in use, and so far the leader -- is this any surprise? -- is Ubuntu Gutsy, with Red Hat / Fedora, Gentoo, and other Gentoo distributions following behind.

At least part of the pitch for the OSC involves creating tools to make it easier to do internal auditing of open source usage -- like FOSSology, which I've mentioned before -- and "to promote the use of more open source software in the enterprise. We know that if we can show companies how much open source they and their peers are already using, they will feel comfortable using even more."

I'll be running scans of my own systems to see what turns up.  I have the feeling I'll be surprised to find open source in places where I never expected to find it.