The "leap second" made the Linux kernel hiccup, which wasn't good for many websites

Reddit, Gawker Media and Mozilla were among the major sites that experienced issues Saturday at midnight when that extra second was added to the world's official timekeeping systems to keep spinning-Earth-based clocks in sync with atomic ones.

Wired.com says the problem is in the Linux kernel. "A Linux subsystem called hrtimer — short for high-res timer — got confused by the time change, and suddenly sparked some hyperactivity on those servers, which locked up the machines’ CPUs." The whole post is here.

I like this quote from Linus Torvalds:

“Almost every time we have a leap second, we find something,” Linux’s creator, Linus Torvalds, tells Wired. “It’s really annoying, because it’s a classic case of code that is basically never run, and thus not tested by users under their normal conditions.”