Well since they aren't giving us an update, I'll take a stab at what's happening. I work for a asp.net development company which is the same thing hbd is built on and when I've seen sites/apps take a performance hit like this in the past, it's typically been a hardware failure; my guess would be a memory card has gone bad or something related to that to reduce the processing power on one of their servers. Or I assume/hope they have multiple servers and one died or is in trouble so processing is down to less than capacity. I wouldn't be surprised if they tell us that we will have some down time coming up to swap it out.
It certainly would be nice if they communicated with us in some way so we had some kind of expectations on the return of normal service.