Stoodle is a free online collaborative whiteboard tool hosted by CK12. On Stoodle you can create a whiteboard space and invite others to use it with you. Registration is not required in order to use Stoodle. In the video embedded below I demonstrate the features of Stoodle.
Applications for Education
One of the best features of Stoodle is the option to import files from a wide variety of sources including Dropbox, Google Drive, and Evernote. Students could use Stoodle to import a file, highlight portions of it, draw on it, and chat about it in real-time as part of peer editing exercise. Stoodle could also be used for peer tutoring sessions on math problems as the whiteboard allows free hand drawing on iPads.