I have a question about some css. Do I post it here? If not here, where?
Try Doctype. That site is targeted at web design questions, which aren't really webmaster-related.
Whoa wait a second... I've seen this happen before... is Doctype going to end up like UXExchange.com? (i.e. with a newer mainstream SE site replacing it in a few months) Dec 29, 2010 at 19:34
@danlefree Doctype is not an SE site, although it has similarities. It is about web design, while this site is on webmastering - really two different things. Dec 29, 2010 at 23:26
I would actually suggest Stack Overflow. There are currently 23,946 questions tagged
css and 31,479 tagged
html so you'll certainly get good answers more quickly there.
If your question is less code-oriented and more management or "philosophical" related, it is perfectly fine to ask it here on Pro Webmasters.