As often as I found myself gritting my teeth reading this post about the overhead that comment spam causes administrators of online content a little less rigidly defined than weblogs, forums in this case, a lot of the choices this admin made are pretty damned smart. Yes, the captcha in order to sign up for accounts is obvious but the requirement that emailed registration links be clicked within 30 minutes of the initial request is a much tighter gap. I tend to disagree with the value of blocking large numbers of IP addresses as this becomes outdated rapidly and tends to cause problems with legitimate users who draw from the same block as a machine compromised by spammers. This also creates process overhead for your server as the list become longer and longer. Other than that small disagreement I think this is a pretty good case study on getting comment spam under control at least from the perspective of freeing admins from spending huge amounts of time doing manual tweaks to configurations.