Might also be that the ISP found a problem and fixed it.
Edit: ... which is looking plausible because utilization on the machines is starting to go up. Nothing dramatic or performance-threatening, but noticeable on the graphs.
I swear, I'd love nothing more than to be so freed up from everything else that I can spend 2 weeks doing nothing but going through every single bit of the software with a fine-toothed comb to make sure everything running as absolutely efficiently as possible.