This example shows the Florida group page. Using the tag "cloud" on the right, you can select the topic that most interests you to see the links available. The size of the font quickly tells you which tags have the most links. Yes, this is a pretty basic directory at this point, but as more people join this group and add their own links it will increase in value - a grassroots effort.
My first group experiments are set up for state resources. Florida and Georgia are my biggest research areas and I'm a native Floridian so I've got the skinny on resources in my area. I don't have to suggest a link be added and then hope someone posts it, I just do it myself. In the process, I'm adding value for all researchers. Tagging sites like Diigo give us the opportunity to share our knowledge with those we know - and those we don't. With little effort on our part, we can build a valuable research network letting everyone participate and benefit from the results.