Diigo has been around for awhile. It is a useful social bookmarking tool that allows you to share websites with others who view your Diigo library. A simple toolbar that may be added to your browser allows you to bookmark any site that you are viewing. When adding bookmarks, you are able to designate tabs and select categories that you have created to which you want the website to belong. Also, at the time that you add the bookmark for the website, you are able to share the link and your tags with any group to which you are a member within the Diigo community.
Diigo community allows for groups to form for sharing bookmarks of a common interest. I belong to three different communities. Between the three communities, I receive on average about 2-3 websites per day. What others share through the communities helps educate me on the accessible websites that might help me with my teaching, student learning, professional development, collaboration, and more.
There is so much more to Diigo than what I have added here. Visit the site to learn about additional benefits to using this social bookmarking tool. Also, you may search my bookmarks for Diigo (http://www.diigo.com) to locate supplemental information.