Diigo

Diigo is a social bookmarking site. I know, your saying "Great, another bookmarking site to learn how to use!". Yes it is but it has some real potential as a great teaching and learning tool. Not only can you bookmark a site and get to it on any computer that is internet capable but you can highlight parts of the site (article) and even add sticky notes to parts of the article. You can create groups and start group discussions. One of the best features is that you can tie all the bookmarks you add to your delicious account (another social bookmarking site). Check it out! I think once you learn how to use it that you will really like it.