"Projects like OpenHatch will even help you match your skill set to a project in need. So what's holding you back? Time? Lack of interest? Difficulty getting started?"
Not knowing about OpenHatch until just now may be a part of it.
As an artist, I've contributed a fair amount of material to the creative commons ecosystem, and I've posted some tutorials for open source projects that have a small user base, but other than that, I have no way of knowing what skills of mine could be useful to anyone working on a project, or what holes they need filled.