Prior to the beta launch, there was discussion of whether this site would be limited in scope to open source software. The strong consensus was behind an answer that argues:
If the scope does not include significant areas of interest to just the open-source world (licensing, hardware, DIY projects, robotics, whatever), then it really doesn't need to exist.
With that in mind, it's still likely that most of what gets asked at first (and maybe indefinitely) will be about software, since that's where the concept of open source began/is strongest.
Should we use an explicit tag to categorize questions about software development? Or do we intend that anything not explicitly categorized as hardware, robotics, etc. be assumed to be software-related?