FuelPHP, as a PHP 5.3+ framework, relies heavily on namespacing to separate the different components of the framework and of your application, to make the code as portable as possible, and to prevent any collisons in class names when you're moving bits of your application around.
By default, the exception to this is your main application code, which resides in APPPATH/classes. All main application classes are defined in the global namespace (they do not have a namespace set), and use the cascading file system to create unique classnames.
While this makes it easier for the novice to start using the FuelPHP framework, it will create more complex class names, and it will make those classes less portable or interchangeable.
