If we are to re-brand as design.stackexchange (See here, here, here and here) we need to define what a design stack would be about. Jeff Atwood just said this:
I like the idea of broading the scope to 'design' so long as we have a good list of valid topics that we consider to be 'design' and people encountering the community would not be confused by this
After all, as someone pointed out on Area51 it can't just be everything with design in its name. So with that in mind, have an attempt at defining design as it should apply to a theoretical design.stackexchange. Vote on the best answer and we should had a good understanding from which we can build on-topic/off-topic questions from.