I found the October 2003 Microsoft Word file in which O'Reilly editor Dale Dougherty proposed a new series of "Web 2.0" conferences. The one surprise is that the idea was originally much more machine-oriented.
The first wave of the web was closely tied to the browser. The second wave extends the applications built on the web server and it will enable a new generation of specialized clients and automated web applications. (Emphasis added)
Four years later, as the saying goes: Web 2.0 is made of people.