The term Web 2.0 reminds me of the word eBusiness. But at the same time it also reminds me of the words Jet Ski, Coke, Kleenex, and the like. The point? People will use words in context however they want to, even when the true definition doesn't suit the need. The use of the word naturally becomes more frequent as it reaches the coveted "buzz word" status. This is mainly because the use of the word can make the author (or speaker) sound more intelligent, up-to-date, or like they are virtually living and operating on the razor's edge of technology.
Web 2.0, like eBusiness (may it rest in peace), is an emergent word that turns heads. The word will come and go just like Vanilla Ice and Y2K. But for the time being, the phrase will find its way into marketing pitches and many people will use the word and give themselves a virtual pat on the back for sounding cool and credible.
I must say that it does drive me crazy when the phrase is used in the context of visual design. Web 2.0 sites are all about web based service offerings, not design trends. They are about usability, not bold colors, white space and bigger text boxes. You may argue that there are common design elements across many web 2.0 sites, but really that just means that we are finally getting to a phase of functionality driven (or purpose driven) designs, and moving away from design driven functionality. Bottom line, keeping "functionality first" is something that is long overdue for the web world. But know that "functionality first" includes the site's scope for content. After all, getting a user to the appropriate content is a matter of functionality and navigational flow. Content is King, and always should be. Think of functionality as the King's cabinet (or the knights who carry out the King's wishes). Design in the merely the house they live in.
If I most go on... what makes a potentially great site magically terrible is when design elements drive navigation concepts and functionality. Hear me now; that is backwards. That would be like hiring a landscaping company to give your front yard a make over, and never showing the landscapers the yard. Items like the size of the yard, amount of grass, location of the driveway, sidewalk, and existing trees, might prove to be useful before blindly marrying into a landscape concept.
In closing, we should all let Web 2.0 be what it is. It's a term to encompass the natural evolution of the internet towards using the web as a platform. Concepts such user importance, stickyness, and building for mass scalability are all part of the party, but the whole world need not throw around the term like it's the latest lyric in a popular song.