Scribblar - Simple, Effective, Creative Collaboration

Scribblar is a free, simple service designed for creative, real-time collaboration. Using Scribblar, users can collaborate on the creation and editing of images and drawings. If you have an image you can upload it to your whiteboard where you and others can edit it or comment on it. The commenting can take place directly on the whiteboard or in one of two side bar chat options. Users can chat in text or in voice.

You can create a Scribblar room without creating an account. However, if you choose to create an account you will get some additional free benefits like locking and unlocking rooms, naming of rooms, and privacy controls.

Applications for Education
Scribblar could be a great tool for students to use to comment on and peer critique art work and graphic designs. This would be useful when students are creating slides for a presentation or a creating other original designs. Scribblar could be a more effective collaboration tool than some its competitors because it does have two options for dialog, text chat and audio chat.