It's a common "problem" when designing a database to predict the maximum length of entries. So Google decided that a 32-bit integer for the views counter would be enough, since it can hold a number up to 2,147,483,647... But PSY was not on the scene yet.
"Gangnam Style," the South Korean pop star's enduring video phenomenon from 2012, has surpassed 2,147,483,647 views on YouTube, maxing out the site's original view counter.
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," wrote Google, which owns YouTube, in a blog post this week. " 'Gangnam Style' has been viewed so many times we have to upgrade!
Which reminds me of something that a friend told me back then... He told me that PSY announced that if his video would become viral and exceed 1M views, he would dance naked... I do not know if this is true though.