Twiddla is described as 'Mark up websites, graphics, and photos, or start brainstorming on a blank canvas. Browse the web with your friends or make that conference call more productive than ever. No plug-ins, downloads, or firewall voodoo - its all here, ready to go when you are' and is a web conferencing tool in the office & productivity category. There are more than 50 alternatives to Twiddla, not only websites but also apps for a variety of platforms, including Windows, Mac, iPhone and iPad apps. The best Twiddla alternative is Miro, which is free. Other great sites and apps similar to Twiddla are OpenBoard Whiteboard, Zoom, BigBlueButton and Briefing.