No one has to use the term web2.0, there are perfectly acceptable alternatives, such as the Read/Write web or the two way web.
When I hear people use the expression, I think, "they haven't read the Paul Graham article"
The fact that Google is a "Web 2.0" company shows that, while meaningful, the term is also rather bogus. It's like the word "allopathic." It just means doing things right, and it's a bad sign when you have a special word for that.People just use it because it sounds like they are modern, hip and up to date. I looked up my references to it in my old blog and was pleased to note that I was suspicious from the start. Although not entirely meaningless, use of the expression, IMO is evidence that the speaker is not familiar with the history of the web and / or too accepting of the latest fads.
The Read/Write web was the way the web was always meant to be used by its inventor, Tim Berners-Lee.
Now that the term has been trademarked as a business slogan by O'Reilly, well isn't that a good reason not to use it, when there are older well established alternatives.