I have re-enabled anonymous comments, subject to processing by Mollom's spam detection service. This will not affect authenticated users, who are excluded from the processing. I will be closely monitoring how effective this solution is, and hopefully the results will be good. For those wishing to comment without creating an account, the process should be unaltered unless the service detects that you are posting spam (in which case the comment is dropped) or it is unsure (in which case you will be given a CAPTCHA challenge before the comment is accepted).