Nevertheless, the actual TeacherTube video, Gliffy Tutorial, will give you ideas of what you can do with a free online graphic tool such as Gliffy. Although the video picture isn't all that clear, the demonstrator's voice is quite audible.
As the demonstrator says in the video: If your register online, you can try Gliffy for free. I used Gliffy to produce the graphic in the post, "Student blogs are springboards to WinK" (2007.03.24). Below are a couple other diagrams that I've made with Gliffy, one about learners and the other for teachers:
(The LTD Project Blog, What is mainstream? 2006.08.30)