If you're to believe Eric Schmidt when he says 'millions' and put that at 3 million users (being generous), guessing that each user uploads 20 megabytes of content (again, generous) thats:
3x10^6 × 20 MB
6x10^7 MB or
60TB
Sanity check or does that not seem like a lot of resources to allocate to a project of this size?
Edit: formatting
So probably they had allocated some amount that made perfect sense while testing, but was too low for the full rollout that seems to (effectively) be happening now.
It doesn't change the fact that 60TB is tiny for a company whose every product involves storing enormous quantities of data and serving them at monstrous scale.
And the amazing part is if you are in an open event where Google is talking about their infrastructure in general terms you will realize that that has to be mouse nuts compared to the amount of 'spinning rust' they have going on at any one time.
And Google likely gets them quite a bit cheaper than that.
For google it's a rounding error either way. They measure in Petabytes, not Terabytes.