It is not possible to have a project be given either a tag, area of interrest, or any other type of assignment. This means that the user is left with the tedious choice of setting tags to each individual task him/herself, give projects a name to distinguish themselves, or just have all projects in a big heap. This is not a good solution, I would call it a bug for a system said to be a GTD system.

The best solution would probably be to have a proper Area of interrest assignment, but tags would be a decent solution also.