Update edit (4 Mar 2016):
Forum is now read only. Development eneded.
viewtopic.php?f=81&t=6563
And indeed it is not possible to reply or add new threads.
I think this was a rude move of CryHam or whoever was responsible for this. Even if Stunt Rally will not be officially developed anymore, there is still plenty of reason for the community to discuss Stunt Rally, post custom tracks to share with others and much more. Please re-open this forum.
If you, CryHam, do not intend to use the forum anymore, that's fine. But please don't prevent others from doing so. It just needs to be clearly announced that there are no official updates to Stunt Rally anymore and maybe mention other things which maybe important, so visitors know any new feature requests are futile. But as I said, there is still plenty of reason to discuss Stunt Rally.