Government organizations like the smithsonian are reaching out to educators and others with an online presence. This cool site has lesson plans and lots of great information for arts, science and technology, history and culture, and language arts.
This organization had people vote on the top elearning tools, while I'd put Diigo FAR AND ABOVE higher than delicious, a lot of people just haven't tried it yet. (I still send diigo links through to delicious anyway.) Some interesting items on here.