I'm about half way through an advanced reader of Bill Tancer's Click: What Millions of People Are Doing Online and Why It Matters. It's an O.K. read so far.
He just made a point about Web 2.0 that I think sometimes gets overlooked in discussions. While he holds to the traditional definition of Web 2.0 as being Web sites where user-generated content is the focus, he showed through some research that the easier a Web 2.0 site is to use, the more likely there will be participation. That's right on.
This week my own experience with the principle of Web 2.Easy involved two beta sites: switchAbit.com and Ping.fm. Both sites do the same thing. I have no idea if one is better than the other. All I know is that I gave up on switchAbit within about ten minutes after reading and rereading and rereading the instructions. So I don't know much about Dave Winer, whose blog first alerted me to switchAbit. Here's something to consider though, a Web 2.0 application that updates your status on various social sites should sound and operate nothing like Assembler. There are other applications out there for this purpose, including Six Apart's Facebook app Blog IT. But if you want Web 2.Easy, go with Ping.fm. You can try Ping.fm with the beta code "tastyping" if you want.
So the real "power of the Web" seems to me to be a combination of 1. User generated/moderated content 2. Ease of use and 3. Connectedness. Put in the opposite order, if I can connect easily by participating online then I'm using a Web 2.0 application.