As teachers we used to pat ourselves on the back for using technology in the classroom if we got students to put some words into a search engine and use the internet for online research. That was the first wave of Web technology - Web1.0 where users were generally passive and received information from the internet.

Web2.0 is the second generation of Web technology which enables students (and teachers and all users) to participate more actively and create material, socialise, network, and access and organise relevant information easily. Students are no longer engaged by the passive use of internet technology. They want to participate. There are ways we can use this new generation of web tools and technology to create interesting educational outcomes for our web-connected students. To learn how you need to use the tools yourself.

An explanation of Web2.0 is given in this video from

For more definitions of Web2.0 - please look at The Connected Classroom wiki here