Last week I attended HKU CITE 2010 symposium on the topic about Learning 2.0. One of the secondary teachers presented a freeware IE plugin Diigo which can highlight webpages and make annotation. He applied the tool for students make note of online newspaper reading and then students can share and categorize each other annotation on news. It is a wonderfull tool for teaching Liberal Studies. http://www.diigo.com/09rpk