I'm pretty sure (given the large scope of the attack) that this is not an attack on specific sites but an attack on one of their border routers. Some sites may be up, depending on which server your site is located on, and whether or not that server is located behind a border router affected by this attack. Also, depending on network configuration and the number of upstream providers they have, some people may still be able to access your site depending on the route they take from their PC to your web site.
By the way, here is the address of the emergency support forum :
http://www.hmdnsgroup.net/forums/
It's located on a different network so not affected by this.