From the site: Twiddla is a no-setup, web-based meeting playground. 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 - it's all here, ready to go when you are. Browser-agnostic, user-friendly.
I've been wanting a place to meet with students and help with homework. This looks pretty good. I can't want to try it out.
Write it on your communicator: Twiddla.