mark, does this repeated request warrant an enhancement bug to include some in-built "guest/anon" account that's locked down and stripped of some basic rights post-wise (html & nasties) for those who wish to run an open forum? I suppose this could be an extension once you work the system out more.
"vanilla was written with anti-spam and security in mind. An open board like that would get pulverized with crap from every kind of internet moron there is: advertisers, bots, script kiddies, etc."
You can, of course, write an extension to allow non-members to post. You'd have to add some things to the comment form like name and email address (optional) intputs, and you'd have to add those columns to the database and make sure they save. But *I* won't be making that an option in Vanilla.