I see that voting for sessions is coming up fast (on 16th Feb). I actually submitted my two solo talks early, at the request of the organizers.
And, for the truly geeky, many of the features in Domain Access inspired Node Access changes in Drupal 7.
So remember to vote early and vote often.
Buy your copy of Drupal 7 Module Development today!
It includes my detailed chapter on Node Access in Drupal 7.