SymbalooEdu is a wonderful site that I just found out about from Kelley Tenkley's amazing blog, iLearn Technology. Symbaloo is ideal for educators to share links w/ students. This is done by creating an environment of sites that educators find and then share w/ their students (similar to the way it is in done in Diigo). Also, a ton of resources and videos can be found on here to help teach educators how to use this social bookmarking tool.
I highly recommend checking out SymbalooEdu by clicking here!!