Via the dot, the EU has released a study on Open Source software. The parts I found interesting was the survey of OSS programmers. Debian is the most popular OS, most programmers know C and C++, almost as many people know Java as Perl.

The question on OSS philosophy is lame - either OSS is a "different way of living" than Free Software, it's pretty much the same, or you don't care. The first option makes it sound like you've joined a cult, but the second option is, to me as a programmer, simply incorrect. Releasing software as open source is objectively different from releasing it as free. Free means anyone can use your software, but only you can make changes to it and redistribute it. Open means anyone can modify it and redistribute it, even if you choose a license with restrictions (e.g. GPL). It seems to me even an anti-open source programmer would agree that open and free are different things, but they wouldn't pick the first answer because it sounds religious.