The crazily popular Gangnam Style video from Korean pop start Psy rung up so many views (2 billion and counting) on YouTube that it broke the counter's ability to keep up. The 32-bit register just did not have the oomph to keeps tabs on all those viewings, and so YouTube had to up the counter to 64-bits.
"We never thought a video would be watched in numbers greater than a 32-bit integer (=2,147,483,647 views), but that was before we met Psy. Gangnam Style has been viewed so many times we have to upgrade!" said Google.
"Hover over the counter in Psy's video to see a little math magic and stay tuned for bigger and bigger numbers on YouTube."TheInquirer