But what if a site owner could charge commenters $0.01 per comment? Using technology like BitPass it would be possible to configure Movable Type in such a manner. By restricting access to the comment CGI script and requiring the commenter to enter a BitPass login, the owner of a busy site could make a few bucks a day, at least. Heck, most people would probably be willing to pay $0.10 or more to leave a comment.
Charging to leave comments would also eliminate much of the hassle involved. People would be less likely to post spam, and even though the cost-per-comment would be low flame wars would get expensive. When people have to spend money (even small amounts) to access a service, they're generally more careful and conservative.
I'm hardly the first one to come up with this idea, but I became aware of the BitPass technology through an email from Bill Hobbs (who's moving to www.billhobbs.com soon). Here's a draft document from BitPass explaining how to charge access for scripts. It's the wave of the future, folks.