- Level 3: The application could ONLY exist on the net, and draws its essential power from the network and the connections it makes possible between people or applications.
- Level 2: The application could exist offline, but it is uniquely advantaged by being online.
- Level 1: The application can and does exist successfully offline, but it gains additional features by being online.
- Level 0: The application has primarily taken hold online, but it would work just as well offline if you had all the data in a local cache.
20 Jul 2006
Tim O'Reilly about the hierarchy of "Web 2.0-ness":