There is no single, clear, definition to Web 2.0, since it is much more then advancement of web technologies. John Seely Brown made good quote material when he said "Web 2.0 is a profoundly participatory medium". Tim O'Reilly, the man who originally coined the term Web 2.0, made an excellent list while trying to clarify what the term Web 2.0 meant:
Web 2.0 means more collaborative work, information sharing, inviting people to participate, giving them more power to voice their opinions. Sites and applications are more interactive, more rich in media, and give better user experiences.
Loosely quoting O'Reilly: Trust your consumers. Let them play. Participate, don't publish. Listen, don't shout. Remember, your site should get better if there are more people using it. And finally: Web 2.0 is an attitude, not just technology.
Despite rumors, and us Google-geeks waiting for an actual hardware phone, Google didn't publish one, it published "Open Handset Alliance", and "Android".
Android is supposed to be "first truly open and comprehensive platform for mobile devices. It includes an operating system, user-interface and applications -- all of the software to run a mobile phone, but without the proprietary obstacles that have hindered mobile innovation."
I knew there was a reason I didn't start coding with Symbian, lol. I guess this "old" project manager found a new hobby. ;)