Less is more. While it is important not to squelch interest and expression, it is also true that quantity on the Internet can be overwhelming. This observation also relates to moderator's communications. Too many questions to consider or probes in rapid fire, can cause participants to wonder what to respond to and leave them feeling they must respond to all. If it can go wrong, it will.
Technical assistance is key.
The organization that is able to set up a listserv usually will also offer some assistance in technical problems which are bound to arise. Be prepared to live with the frustration of some problems that cannot be resolved neatly or quickly. Moderators are well served by learning the vocabulary of the Internet in order to be able to pose the right questions to the technical support people. Check with your system administrator if you are not receiving mail for a few days. If the system administrator receives non-delivery notices, the person will eventually be dropped.