Still not clear...
OK, I don't know you but if we keep this up and neither of us think we're being clear, we should be married. (joking of course).
I can see where in the way you're looking at it, Web 2.0 is a buzz word. But consider that there never was a Web 1.0. If you think of the Web, you inherently know what it means simply by the use of it in society. Most people who use it have no clue about CSS or even HTML but they know it as the Web (1.0).
Spoken languages are ill defined, especially in America and by Americans. If I asked you "What's up", you would know not to look up to the sky to see what's up there. Yet when the phrase was starting to be used, it wasn't defined in any dictionary. And if it wasn't in a dictionary, you could argue that the term really doesn't exist and is, say, mythical. But in reality, everyone in America quickly came to know what it meant and now it likely is defined in some reputable place. But even now it could be usad as 'Hello' or 'What are you doing?'. Neither of these two definitions even nearly resemble each other but when someone says 'what's up' you take the statement within the context that it's presented.
I think (respectfully) that you are missing the context and that you need to define yourself. In a geek party conversation, I would never argue that XHTML is or isn't Web 2.0 because there is no defined context (which is what I think you are searching for).
There is a blur between Web '1.0' and Web 2.0 but I don't think that makes it a buzz word. Originally we had HTML, now we have XHTML. We now have CSS and SVG and others. All of these work together.
SVG, for example is relatively new (about 9 years old or so) and got strong about 2002 then died down and is now coming back. It's still not entirely defined, and considered unfinished. Yet still it works with CSS. If it wasn't developed to work with CSS, there would be no use for it and it wouldn't survive. Thus I would consider it a Web 1.0 technology.
I know this is all fuzzy and I think that's where the author had the problem. Web 2.0 is a concept similar to driving home from a long trip and saying "We're almost home." There is no line as to where 'almost' is but just the same, that place does exist.
There isn't a clear line where Web 2.0 starts, but it is here. I would call it more of a brand name though rather than a buzz word. Many knowledgeable web consumers and novice developers (myself included - I'm considerably more experienced in developing, managing and interpreting standards than I am as a software developer) need a simple name for these types of changes that have occurred and Web 2.0 is a simple way of putting it.
