I enjoyed using del.icio.us.
This is the link to my account http://del.icio.us/batllo

It was interesting to see other environmentally friendly web sites that people had linked to. I especially liked Treehugger.

Wikis

The wikis seem to be a good educational tool for explaining things and showing people where to find information on certain topics. My wiki is on green sites. The address is https://greenepage.pbwiki.com/