There is great debate about when a web application is "thick" versus when it is "thin". As a result, application thickness has a spectrum rather than a boundary. However, here is a rule of thumb to help make the determination -- the "back button test". If the back button doesn't work in a web app, it is almost certainly a thick app. If it does work, then the app is quite likely to be thin. The test isn't perfect, but it works quite well in practice.
... until the collector arrives ...
This "blog" is really just a scratchpad of mine. There is not much of general interest here. Most of the content is scribbled down "live" as I discover things I want to remember. I rarely go back to correct mistakes in older entries. You have been warned :)