Six Apart is planning to introduce an authentication service called TypeKey to control comment spamming.  Not much detail hasn't been released yet, but I think such a service will be good for the blogosphere as long as it is done right.  A typical cause of failure for such schemes is unnecessary tight security.

Security is a relative word after all and I don't think security requirements for blogging is stringent enough to call for draconian measures that will surely discourage commenting.  Also, I feel that some room should be made for misbehaviors.

One such scheme is to separate the comments into two groups: good comments and unknown comments.  Unknown comments are displayed away from good comments and are decayed over time to avoid pileups.

When a comment is posted, the comment server checks to see if the commenter has a 'blogger-cookie' and whether it was given 'welcome' status by the blog.  If so, then the comment is considered good.  If the cookie is missing or is not granted 'welcome' status, then the comment is unknown.  'Welcome' status is granted by the blog owner while shifting through the unknown comments.  'Welcome' status can be revoked with a single click or via checkboxes.

Unfortunately, I think Six Apart's plan is more ambitious which could spell trouble ahead for Six Apart and MT users.  I hope they make the right decisions.

Update:

TypeKey seemed to have caused a firestorm of posts, mostly negative or skeptical.  Scott Loftesness, a mother lode of rich knowledge and experiences on consumer authentication, has a more positive opinion.  My experience with authentication is limited to design and implementation, but I also think privacy issue is overblown, particularly since search engines can find my comments anyway.  Yes, it take some effort to collect them all, but one doesn't need to read them all to form an opinion about me.

Here is a pseudo-code version of an alternate decentralized solution which I amusingly named TypoKey:

on comment submit:
   if has typokey cookie
      if typokey is valid and approved
         comment is good
      else
         comment is unknown
   else
      set typokey cookie
      comment is unknown

As I mentioned above, good comments differ from unknown comments in that they are displayed at more convenient location and persists longer.  If the commenter does not wish to use typokey, then they can choose not to by disabling cookie or by not checking 'check-me' checkbox although their comments will be classified as unknown.

Checking check-me checkbox?  Heehee.