This document provides information about the online collaboration tool Twiddla. It defines Twiddla as a free online whiteboarding tool that allows users to mark up and interact with web pages in real time. Some key advantages mentioned are that Twiddla is free, accessible anytime from any web browser without plugins, and allows users to interact with web content while marking it up simultaneously. Examples of using Twiddla for teaching include holding online office hours where the teacher and student can draw and write on a shared whiteboard to work through problems.