Social Bookmarking in Plain English
Uses the "Delicious" bookmarking service in the example, but Diigo is best for educators.
Great example of how social bookmarking can be used with students so they can find and save information. A very useful feature is the private or public Groups, which can be based on a grade level or unit of study.
Once a site is bookmarked in Diigo, it can be shared in a variety of ways. Below, my latest "PLN Gems" are shared using the RSS gadget. I have been using Diigo since 2007. My first foray into cloud-based booking was with Blogmarks and Delicious in 2004.