Webmasterworld’s administrator trillianjedi started a thread where he gives a short and clear definition of “Web 2.0” that you could give to the CEO of your client company :

1. A BS framework enabling your website designer to pursuade you that you need a website redesign because your existing wesbite is “… just so Web 1.0″

2. A “mash-up” of different technologies. Web meets TV meets radio and other media types. See YouTube and Google “podcasting” for examples.

3. Community is King.

4. Push technologies, dynamic HTML and AJAX (yeah, basically all that stuff we started doing in 2001).

5. Lot’s of 3D stuff (OK, I admit I’m scraping the barrel with that one).

While the CEO could argue that fancy stuff such as AJAX or 3D animations already existed before, you really should convince him that “community is king” and that people just love mash-ups.