I am just as much a conservatist in BBS software as anyone else. That is exactly why we migrated to PunBB.
On the other hand, there is a huge difference between minimalist and perceived/relative security. I can safely tell you we won't be allowing anyone to register to our forum without having a valid email address and user name. [and most likely enforce entering their first and last name at registration.] Of course, this is just in our setting, however I am sure anyone who runs a large board will agree.
When you have a board that becomes reasonably popular, it only takes one baffoon to bring it all down through hacking at worst, to lurching profiles in the least. In the later case, that pisses people off to know they had their email address screached off what is supposed to be a reasonably secure community.
We used phpbb. At the time we started using it was years ago; it was the second version released and those days was the cat's meow. Everyone loved our new digs.
Today? Phpbb is the most hackable software on the planet, with script kiddies figuring out new ways to break in and do bad things every day. In just one short year, we were hacked three times. Not due to stupidity on our part, but due to security issues with that software.
In short, it's gotten to the point where browsing Phpbb's forums is a necessary, presidential, daily security brief. That's a fucking shame.
You have no idea how much we'll love getting away from that board.
What adds insult to injury, is posting your problem on Phpbb's forums. I clocked my post; within one minute, my post had slid down the page to the bottom of a huge list of complaints. The number of people posting was almost to the point of the ridiculous. As for my own post? There is no way I was going to get help and I knew it.
In summary, sure you can have anyonmous posters. You can even allow people to post without registering at all. I agree with Paul, as everyone who would show up as a guest when everyone is a guest, well ...who would you be talking to?
I recognize there is a difference in Minimalisim and my own post comparing it to Security. My point has much or more to do with creating communities where the people who use it feel relatively secure, and can indeed leverage their personalities in a positive way.
Something can be said that by creating communities can potentially offer more features to users who took the time to register.
IMHO, allowing people to post/reply/read anything as anynonmous and without registering is certainly not the way to do it.