Manage tasks with your to-do list
Keep track of what you have to do, and what you've done.
Never forget about homework or a quiz.
Easily search and share notes
Search and bookmark notes.
Share notes with your friends and groups.
Take, edit and share notes online
Take and store your notes online.
Edit and revise notes with peers.
Look-up and define words with your Workspace Utilities.
Search engine specifically for education
Topmarks claims that "All of the content on Topmarks is carefully reviewed by qualified teachers and regularly re-checked because of the changing nature of the web."
via http://paulhami.edublogs.org