For now, ask me, via a post in this thread or in site feedback. But, I’d actually like to hold off on creating categories right now, because of the pending site restructure. And particularly, I’ve grown to strongly believe that categories are the wrong grouping for SIGs. We probably want to use tags, instead — categories are better for really big distinctions (Fedora Project, CentOS Project) or for functional differences (see discussion in that thread).
So right now, my suggestion is to just start talking in the general CentOS, and we’ll figure out how to organize as a further refinement.
Or in other words: premature categorization is the same problem as premature optimization. 