Notifications in what sense? To your email? If so, it's usually your provider blocking them. I used to get them to my email but when theymos made some changes to the forum a while back I stopped getting them at all, then one time he changed something else and they started again.
Yes, to my e-mail. And I don't received notification for your reply, even though I started this thread. Btw, I doubt that my provider is blocking them. There is something else...
EDIT: Are you sure that no changes were made in the past few days?