Web 2 point what?

What is web 2.0? - The second phase on the Internet I hear. With so many competing companies and applications it's all a little overwhelming to me. I'm looking forward to making use of these 2.0 resources and have been active on myspace and facebook for some time now, igoogle, google reader, blogspot, and really everything google. I recently joined LinkedIn too. I just want everything to happen by using one button (a google button I hope). I hear about digging this and delicious that so I guess I have a lot to learn. Look at all this...