More than a decade after the Y2K scare, a single extra second has caused problems for a number of notable web companies. The leap second
— a one-second adjustment added to atomic clocks to synchronize it with clocks based on the Earth's rotation — occurred on Saturday night and caught a number of companies unaware. Reddit tweeted
that it was having Java/Cassandra issues due to the extra second, while Mozilla filed a bug report
also due to leap second-related Java issues.