The Fiction_L Listserv managed by the Morton Grove Public Library. Subscribe to the listserv to follow current issues in reader’s advisory services and ask questions http://www.webrary.org/rs/flmenu.html
Search the archives to find answers to RA questions. http://www.webrary.org/rs/FLarchive.html
DorothyL Listserv focused on Mystery writing. Subscribe through http://www.dorothyL.com Broader participant/audience including authors, publishers and librarians. More focused on the business of mystery writing, but does have some reader’s advisory threads. This list has a searchable archive. http://listserv.kent.edu/archives/dorothyl.html
GNLIB L Graphic Novels in Libraries Listserv for librarians interested in Graphic Novels. Subscribe through http://www.angelfire.com/comics/gnlib/ .
Science Fiction and Fantasy Listserv http://sun8.loc.gov/listarch/sf-lit.html Moderated by Library of Congress. Has “searchable” archives.