Could I get a clarification on the use of bases?

I suffer from acute basenitis. I base just about every model I make. It’s simply a personal preference as I feel that it makes the model look much better when it’s mounted on a simple base rather than simply standing on a shelf. Makes it more robust too...

So, if I mount a tank on a plain base, say with a dirt road and a bit of grass, and have a commander peaking out of the turret, would it be a diorama?

As opposed to, for example, mounting the tank on the same base but now placing the crew around it.

Guess that what I’m looking for is a sort of clarification as to where the line between a diorama and a non-diorama is drawn...

On a completely unrelated note, do all of you plan to post build-logs or are you keeping things secret until it’s time for the judges to issue their verdict?