Insightful if technical bit about new architectures for interfaces - in this case, Google's new use (Gmail, Orkut, Suggest) of flexible server-side updating via javascript xml http requests. In short, slashing transaction costs for users by feeding data to the client more efficiently and less redundantly.
Highly recommended - I just noticed this myself and deconstructed Gmail a few days back - very impressive stuff. What we might call radical innovation, in fact.