BGRASS-L is the best place on the Internet to talk about bluegrass music. The list's charter states as it's purpose: The discussion of issues related to the International Bluegrass Music Association (IBMA); and of Bluegrass and Old-Time music in general, including but not limited to recordings, bands, individual performers, live performances, publications, business aspects, venues, history,performances, publications, business aspects, venues, history,legal & ethical issues, radio, TV, you-name-it. Early commercial country music is also an acceptable topic." BGRASS-L is a *very* active list; fifty or more messages a day isn't unusual. (I recommend setting the list to DIGESTS to avoid being overwhelmed.)
The charter sez:
This is a discussion area for anyone who has an interest in the broad area of country music. This includes traditional country (Ray Price, Faron Young, Bob Wills, and the new traditional sounds of George Strait, Marsha Thornton, and many others), "Hot New Country", what I suppose you could call pre-country (Jimmy Rodgers, the Carter Family), and anything else semi-related, including a lot of the 50's-60's rock that many country bands embrace (e.g., Credence Clearwater Revival).
Postcard2 is a mailing list devoted to alternative country bands in the Uncle Tupelo/Wilco vein. In fact, it began as an emergency list when the UT/Wilco mailing list's server was down for several weeks; when the regular list got back up and running, the listowner, Laura Levy, decided to keep the second list going to discuss all the bands people kept going "off topic" to talk about. It's a pretty lively list, so for some the digest option will be required!
This list is meant to be a meeting point for all the 50's rock'n'roll and rockabilly adicts. The welcoming message invites members to "use this list for sending us info about the next gigs in your area, writing some gig reports, talking about the bands you dig and about the bands you dislike...In fact all the subjects related to the rockin' scene and 50's life style are welcome."