css-discuss is a mailing list devoted to talking about CSS and ways to use it in the real world; in other words, practical uses and applications. While theory and ideas for the future are interesting, they do interfere with our mission to help people get the most out of CSS today, so we tend not to spend a lot of time on theory. There are other lists and groups for that sort of thing anyway.
The list sports a very large membership and strong sense of community. This particular community is welcoming of new members, but remember that any large group of people who have been around for a while will have evolved a set of mores and limits. If you plan to join us, please read the list policies before you make your first post. And seriously consider a look through the list archives to see if your question has already been addressed. We're usually pretty tolerant of repeated topics as long as they're spread out over time, but if you ask the same question someone else asked two days ago, you're unlikely to get many responses.
We do our best to help newcomers to CSS and old hands alike, and many fascinating techniques and tricks, some of them documented in articles for respected industry publications, have come out of the list discussion. If you're interested in using CSS in today's browsers, and you want to be a better CSS author, then this list is very definitely for you.