[sorry for the double-post, just realized this is the appropriate forum =]
we have signed with a customer that runs several large announcement-only mailing lists (not spam, but of a commercial/advertising nature).
he has been running the lists with a perl cgi script, which obviously hogged the resources as god knows what. majordomo et al are an option, however they are overkill since the mailing list is announcement-only - something like a bulk mailer would be better. obviously, a web interface would be advantageous.
please post any recommendations/pointers, as well as personal experiences with particular programs.