eduweb is an award-winning developer of digital learning games and multimedia interactives. We create immersive, interactive, and in-depth adventures about art, science, history and technology.
LiveBinders - looks like a good addition to Diigo Free. For over 13 years of age - perhaps a great tool for students and for creating a common place for integrated learning projects
A Site worth looking at for Elementary, Special Education, and ELL students. Some of the tools might be a bit pricey. Look at the Blog and seriously think about an RSS feed. The links to resources are awesome.