Enabling spam-free comments on this blog (Updated)


I'd like to enable commenting on this blog, but I've seen blogs flooded with spam in the past.

Due to my work and other commitments, I can't monitor the blog constantly to filter out spam.

Can anybody suggest a viable solution? Should I ask people to register by SMS, like getting a Facebook account? Should I try the Mollom network-based service discussed in the Drupal site? Will Captchas cause more frustration than adding value?

Update 14 March: I've now enabled unmoderated comments so people can reply easily

If you have an OpenID, click "Log In", and if you want to comment without OpenID, click "Register". I've also raised a bug report because the Drupal blog module should not have been displaying those links and causing people frustration when user registration was completely disabled.