I've used Delicious in the past and think it is fine. It is quite useful to be able to bookmark things in one location and retrieve them from any computer anywhere but I decided to explore Diigo. The possiblities looked more to my ideas of what I want out of a social bookmarking site. I look forward to playing with it more.
For now I used the following tags to find this webiste that I know I will access often this coming school year: "IB", "IB MYP", and "MYP". This is the site that I came up with- http://blogs.triplealearning.com/
The other site I found using the tag "MYP" was: http://mscofino.edublogs.org/2007/06/03/creating-independent-learners-the-myp-technology-design-cycle/ which I know I will go back to and use it to network with another MYP Technology teacher.