From a corporate culture point of view, while the marketing/comms dept are starting to understand all this, part of the usefulness of comment registration is that it helps acheive culture shift in very traditional environments.

To get the blog up and running in the first instance, registration and other barriers act as a reassurance to the powers that be that It Will Be OK. The blog and/or marketing have often have to prove themselves in order to continue so it’s cautious first steps and successes initially. Then they can let go by degrees – especially when they realise that no one is commenting.

Maybe it’s a necessary part of the process. Like a worried parent with a child to protect, they see risk everywhere in the early days then let go in time.