The addition of a leap second to the Coordinated Universal Time at midnight Greenwich Mean Time last night appears to have caused site disruptions for a handful of popular Web sites and software platforms.
The adjustment, which was made by International Earth Rotation and Reference Systems Service, was necessary to keep atomic clocks in line with the Earth’s ever-changing speed of rotation.
Some of the sites affected by the bug was the popular link-sharing site Reddit, Mozilla, the organization behind the Firefox Web browser, StumbleUpon, Yelp, FourSquare, and LinkedIn were also affected by the leap second.
Source: CNET News