Usually when I see that a site is having repeated issues like this, I go to Netcraft and find they are running IIS. However, Netcraft tells me that Hubpages, like the vast majority of intelligent sites, is running on Linux.
I suspect they are just having growing pains. I'm sure they will add whatever number of servers they need and fix any software glitches soon.
The nice thing about having websites today is that it is dirt cheap to throw a mountain of computing power at any problem. The bad thing is that controlling all that with software can still present difficulties.