I've used several Web 2.0 tools in my Info Tech classroom.
Facebook and Twitter: I mainly for personal & professional use to connect with peers and experts in my field. I've also used Facebook groups for teams and organizations which allows us limited, password-protected access to schedules, pictures, photos, discussion boards, messaging, etc
Wikis: Great for definition lists! Assign students one or two words each, they post, others have a revision role.
YouTube: It's is a wonderful teaching tool. I've found many How-To's that I've used in class. Did you know that you can replace the youtube URL with kickyoutube and download the streaming video into something you can use offline?
Google bookmarks: I have students open a Google account and we use that for bookmarking favorite sites. The favorites can go along with them wherever they have a Google toolbar or at Google.com/bookmarks.
Blogger: Our students use their Google accounts to begin a blog. They write about what we've learned in class and follow each others' writings, commenting as well.
Interview with Andrew Warner of Mixergy.com
15 hours ago