When new videos are uploaded on YouTube, for some reason, once they reach 301 views the count seems to stop. The number has led to some confusion on the video sharing site, which is why Brady Haran of the Numberphile channel decided to investigate.
Haran interviewed Ted Hamilton, product manager for YouTube analytics, to get to the bottom of the phenomenon. To start, he asked how a “view” is determined. Hamilton said defining a view is a bit of a YouTube secret. “A view should be a video playback that was requested by an actual user who got what they were intending to get and had a good user experience,” Hamilton said. He said that YouTube thinks of videos views as a currency.
Hamilton explained that after you view a video, a server will give you access to the video then log the view. Then, the log is tallied and aggregated. Hamilton says that after 300 views, the numbers have to be verified in what he calls a “statistical verification process” which ends up taking quite a bit of time. The effort is to make sure there's no "counterfeit" views, which are commonly generated by malicious bots.
But why stop at 301? Hamilton said he wasn’t there when the decision was made to make 300 the stopping point for verification. It's actually due to the code created to determine how many views a video gets. Hamilton explains the process starting at the 5:00 mark, and Haran breaks it down into easier language starting at the 5:50 mark.