Casey Neistat for those that don't know him, is a famous YouTuber. And for other YouTubers getting a mention or an acknowledgement from Casey would be a welcome boost, and could mean new subscribers which could mean more views. Getting more views, leads to more income on the platform.
A while back Casey put out message on Twitter about how to get a shout out from him.
So this other YouTuber I watch known as Metal For Breakfast, just released this video in an attempt to get a mention from Casey.