The ubiquitous buzzword Web 2.0 means something different to everyone, from lickable logos to semantic markup to web-based startups who sell out for millions before they even launch. This vagueness means it’s inadvisable to even mention “Web two-oh” unless you explicitly define what you mean, as there’s no guarantee that the people you’re talking have the same definitions in mind. This can be especially difficult in discussions across multi-disciplinary teams, particularly those involving geeks like myself with a misplaced sense of ownership who are liable to take grievous offense from the term’s misuse. Happily as there is no consensus as to its meaning every use can be construed as a misuse.
Stepping away from the contentious semantics for a second: here’s a brilliant 5-minute video that outlines the current “two-oh” state of the web and it’s evolution from 1-to-many to many-to-many, from one-way publication to two-way participation. (Sound is very optional.)