Quora connects you to everything you want to know about. Quora aims to be the easiest place to write new content and share content from the web. We organize people and their interests so you can find, collect and share the information most valuable to you.
Buzm is a place to keep all the tidbits you have been emailing yourself for years. It uses P2P and TiddlyWiki so you can save, sync and share your stuff without uploading it to some foggy server in the cloud.
edutagger is a social bookmarking service for K-12 learners and educators, allowing you to store your web links online and share them with others, all within an educational context.
Egnyte is a Web 2.0 content sharing solution that combines sharing, automatic organization and a powerful search capability. Using continuous synchronization, Egnyte seamlessly integrates the desktop with the web.
SpiderOak provides an easy, secure and consolidated free online backup, sync, sharing, access & storage solution for Windows, Mac OS X, and Linux (Ubuntu, Debian & Fedora)