Many are high-traffic. All of them prefer you make an attempt to check the archives before posting a question. Some search sites for specific lists are listed following the mailing lists themselves. Eazel host several lists of which the Nautilus list is a particularly useful one to know about. The gnome-list mailing list in particular gets a lot of traffic, because people often aren't sure where to ask questions or simply don't know where to ask.
Debian users can head for several Debian mailing lists on the Debian website .
Mandrake users can head for several Mandrake mailing lists on the Mandrake website . Caldera users can head for several Caldera mailing lists on the Caldera website . The best place for newbie questions is the freebsd-questions list. XFree86 lists at the XFree86 website . The newbie list is described as being for general XFree86 setup and configuration problems.