I just took a peek - they don't update their software often. DU still uses PHP 5.0.5, MySQL 4.1 and Apache 1.3. I can only suspect that the ancient, heavily modded, DCForum+ software that DU runs on is locking them down because of compatibility issues.
I'm stunned someone hasn't hacked the living daylights out of them yet. All of the above are full of exploits, especially Apache 1.3