I know this is a very broad topic. If SF&F.SE is the correct forum for this type of question I plan to ask much more specific questions related to the subject.
There is a Comics proposal up on Area 51. But until it goes Beta, it wouldn't be available for such questions.
If I understand your question correctly, this isn't an appropriate place. While I would personally welcome all comics questions that pertain to the science fiction elements of comic books (or even the story elements of comic books with a science fiction storyline) and urge others to do so as well...
Questions that pertain only to the "comic-bookishness" of comic books seem inappropriate. If you're asking about how many promotional cover variations they made for the new Octopusman series, it's just not really on-topic (even though a question about one of those images might be on topic).
The closest you could come to this for a site right now would be the Graphic Design site, depending on exactly what your question is. Things like the quality of the paper, images, etc would definitely be on topic there, but I'm not 100% your questions would fit. You might still take a look there, however.