When to use GWT and when not to

Here's an interesting question, one which I'm still not completely sure about. Firstly GWT is not really that great for entire websites, although Google does use it for many of it's web applications.

I have been using this toolkit, off and on for different projects. I really enjoy developing web application using the toolkit, but it also makes it difficult to keep a website... a website. It makes a website look and feel more like a desktop application, and is programmed in that very same way.

When do you choose to develop something using GWT over traditional HTML? Currently I see it useful for HTML-based applications/widgets on a website, such as a knowledgebase system.

My last use case for GWT is for an authentication framework I am building, it uses Digest authentication. The web app requests a token from the server, then hashes the inputted password with this token before sending the password over the network. Very similar to how HTTP Authentication does it. I know I could have also built it using standard HTML/JavaScript/JSON. I choose this method as most website bots cannot parse complex javascript, and it will ultimately deter from bots attempting to sign into the website. I am also building a registration form using the same method.

I think you've pretty much answered your own question there.

When to use it: Applications and user interaction.

When not to use it: Standard "text only" areas and sites where content and SEO is important.

GWT is a very good toolkit, but it's the same as every other one out there, it's made to allow you to develop applications or even widgets rather then a full site because it's just not practical to load all of the dependencies for each page.