https://groups.diigo.com/group/diigoineducation
Diigo is a social bookmarking site, similar to Delicious. Diigo allows you to save web site bookmarks in a forum that can be tagged for future reference. From there, links can be kept private, shared with individuals, shared with a network of people, or shared with a group of users. Diigo in Education is a group of Diigo users that shares education-related links. As a member of the group, one can post items, post comments on items, as well as view the links posted by other members.