This study of open source software and usability neatly intersects two of my interests: information design (and usability) with open source software.
I've been involved in the open source community for a very long time. I first became aware of "Free software" around 1992 (or 1993?) while I was an undergraduate physics student. I had several classes that required use of the campus computer lab, and the lab manager installed many Free software (such as the GNU C Compiler, the GNU Emacs editor, and other programs) for us to use on the central Unix systems. I found this software to be of equally high quality to the commercial "payware" programs that I had used up to that time.
Later in 1993, I decided that I could use Free software to run my computer, so I installed the Linux operating system on my small '386 PC. I've used Linux at home (and at work) ever since, although I continued to run DOS on my computer for the rest of my undergrad years.
During my undergrad years, I extended my interest in open source software. As a physics student, I had learned some computer programming - and had learned more about it outside of class. In 1994, I started work on my own Free software version of the DOS operating system. I first called this "PD-DOS" for "Public Domain DOS," I quickly renamed it to "Free-DOS" and later "FreeDOS" as much of the operating system was built on Free software.
FreeDOS was my first "real" entry into the open source community. Since then, I've contributed to other Free software and open source software projects, including operating systems, editors, tools, music programs, and games.
More recently, I became interested in information design, through my graduate studies. Usability is strongly related to information design - and in fact, is a method to improve information products.
So in a recent conversation with my advisor, I started looking to communities surrounding usability and "UX". One popular destination is the UXPA - Usability / User Experience Professionals Association (formerly "UPA"). I'm sure there are other communities that have formed around LinkedIn and other social media venues. I plan to join UXPA and LinkedIn communities, even if only as a "lurker" (reading and listening, while rarely posting or contributing topics). What other communities can you suggest?