If you were to log in, you'd be able to get more information on your fellow community member.
You came so tantalizingly close to getting it, with your emphasis on "single browser window". That is the essence of what iPad is, except instead of being a computer with a single browser window, iPad IS the window. Then, by extension, it can become the UI for anything. It is the window without embellishment or contrasting context. iPad places the emphasis on the content of the window/application, rather than the container. I (and apparently others) find it compelling.