Scrapbox - A new style of note-taking that lets you create, discuss, and learn together in one self-organizing space.

Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.

Unit Notes for iOS - A simple and powerful note-taking app.

Workflowy - A better way to organize your mind.

Doceri - Doceri is a scalable suite of products that allows a teacher or presenter to control a computer's desktop, to control audiovisual technology, and to annotate any presentation in real time with the Apple™ iPad™.

Ghostnote - Add notes to anything.