This is Camilla's new blog, and also an early-test site on the http://drupalcloud.mit.edu service.
Biscuit, as in, "nice sysadmin, have a biscuit..."
You should be able to sign up for a CAMS Collaboration Account here: https://idp.touchstonenetwork.net/cams/CreateAccount.action and use such an account to comment. Go for it! If you're signing up directly in drupal with a password, that won't/shouldn't work.