The “leap second” was a one second adjustment made to the atomic clock tonight at 23:59:59 UT (just before 8pm ET). After it went into effect tonight, half the internet — including Reddit, FourSquare, Yelp, LinkedIn, Gawker StumbleUpon, and more — came crashing down. The outages were mostly (thankfully) brief. Here’s how it happened.
The TL;DR version: There is a tiny gap between traditional “rotational time” and the modern “coordinated universal time,” due to the fact that the earth spins a tiny bit slower every year due to tides and internal processes. No clock can accomodate an “extra second,” so clocks are stopped for one second at 23:59:59 in order to add the “leap second” to our universal time.
Reddit, Gawker media sites, StumbleUpon, Yelp, FourSquare, LinkedIn, and Meetup were among the many sites affected for some time.
Continue reading the rest of the story on Buzzfeed