"LISTSERV site administrators' forum" <[log in to unmask]> 
wrote on 02/01/2007 09:08:57 AM:

> Send= Editor,hold,confirm,non-member
> 
> This will require non-members to confirm which will eliminate most 
> of the spam. 

And quite possibly get your server listed as a spammer for all the 
backscatter.  It's better to put the listserv behind a good spam filter.