Right now the only other social bookmarking site that I know of that is geared towards academia is Blackboard Scholar, which is only available to users of Blackboard. Today I found out about Brainify.com which was created by the founder of WebCT. You only need be a member (student, faculty, staff) of a higher education institution to join.
When I signed up, it made me wait about a half-hour while it verified that I am affiliated with a university or college (it used my email address to do so). Once it was satisfied, I received a link in my NLU email to finish the registration process. I uploaded my avatar and added my degree program information: Masters - Education - Education Technology.
I bookmarked my first website (it offers a browser button like other social bookmarking tools) and assigned the site to a topic/category. I had to create a new subtopic, Diffusion of Innovations in the Education > Educational Technology category. The topic I create is permanent and will be used by other people. I suppose this is how Brainify proposes to keep things organized, but I see this becoming quite messy in the future.
Brainify aims to not only help students connect with content, but also with one another. I already see how it is hooking me up with resources for my area of study. Faculty can create groups for their course and provide resources.
I think the site has a lot of work to do. It appears that there are less than 1000 sites bookmarked right now and less than 500 users. And I don't see a way to import/export bookmarks. But the site is just a few months old. And here's something interesting...
"Our intent is that if Brainify ever changes hands (sells), we will distribute 30% of the proceeds of the sale among the members of Brainify."
You get ratings on Brainify, and if the product is sold, you will benefit financially according to your rating!
Watch an informational video about Brainify: