A few literary listservs
subscription information at the web pages below
(most also maintain browseable archives)
 
Cafe-Blue (an off-shoot of the now defunct journals Blue Penny Quarterly and Blue Moon Review.  Originally devoted to discussion of online publication, it has evolved into a chatty virtual watering hole where writers discuss almost anything, occasionally including literature.  Not a workshop site.  Traffic can be high at times.)
CRWROPPS-B (Creative Writing Opportunities--not a discussion list, but regular emails about contests, anthologies, calls for papers, conferences, etc.)
 
CREWRT-L (creative writing in education for teachers & students)
CWUHM-L (“sends out one poem each day, as well as announcements of literary events in Hawaii (marked 'Hawaii'  in the subject line, so that out-of -state and international subscribers can easily delete them), and occasional essays about poets or poetry.”)
New-Poetry ("The NewPoetry List has two purposes: information and discussion related to contemporary poetry. We welcome publication announcements, reviews, essays, open letters, quotes, news items, calls for submissions, and, of course, poems and your commentary." Archived.)
Poetics (University of Buffalo. Focusing on language-centered poetry: Archived.)
PoetryEtc. ("a venue for a dialogue relating to poetry and poetics." Archived.)
TSE (Discussion of T. S. Eliot. Archived.)
WomPo (Discussion by and about women poets and women's issues. A few male subscribers. Archived.)