A board I'm on has about 700 - 1300 members being served from a listserv maintained by a company one of our board members is on. This restricts the ability of other board members to use the listserv unless they are employees of the company.
They want to move to a system where anyone can administer the list.
I'm thinking of switching to Constant Contact or Google Groups. We want something that allows list members to manage their own contact preferences and enables anyone authorized to send emails to the list.