Annotating a book is an important skill for any student to learn. Highlight text, sharing ideas and writing in the margins is a common practice in schools today. Diigo lets you do that on the Web. Imagine a website, you read four years ago, that has your highlights, post it notes, and annotated images saved to your library. Now think about how you can share your ideas and annotations with students, guide them in difficult passages and differentiate the content for certain students. Diigo is a free web based application that will allow you to bring these imaginations into your classroom.