My understanding from skimming the verdict of the second lawsuit which was posted at one point was that because MBshop sold parts it stuck and MB had a case and won. If Mercedesshop.com was just a stand alone forum like say Benzworld, or MBworld it wouldn't have flown.
This is why you still see other Mercedes named forums around.
BTW I still have a Mercedesshop grill badge and decal around here somewhere, waiting to go on my next MB.