He shows us some very deep connections between the geometries of the siting relationships of the Cydonia monuments on mars, and some of the crop circles, and he has therefore, a partial explanation of the circles as an attempt to communicate something important to us.
This seems to me to be the strongest, if a somewhat technically dense, argument currently on the table for crop circles being of extraordinary origin, so I've been surprised you haven't brought it up.
Here's his web site if you want to check into it:
As I mentioned earlier, there is MUCH that doesn't meet the eye.
Hoagland is a bit a hack and a grandstander, and many people cringe at the mention of him. HOWEVER, he does bring up some interesting ideas every now and then... :)