>Is this why the UT couldn't be accessed from my place in North Carolina at 7:58 am EST yesterday?

That would probably have been that.

This has caused problems with not only domains hosted at NS but also DNS tables all over the world.

For example, yesterday, I was able to access UT from various networks but not from iPhone. At the same, I was not able to access levelextreme.com from anywhere but started to be able to access it from iPhone in the next hour. As for the PC, it took another two hours before I was able to. Then, other Web sites I have started to appear one by one in the hours following that. This has also caused problems with email servers and so on.

Add to that, from Montreal, a major storm in the middle of the afternoon which has cut off power at several locations, from a remote network I was at. It wasn't the best day to access the Internet, especially not from Montreal.