Someone who uploads youtube videos, particularly someone who has some what of a fan base. Although it can mean anyone in youtube, it specifically means someone who makes videos.
My Friend: Hi Have You've Heard Of Braso
Me: Yes And He's A Scummy Youtuber Who Milks On Technoblade Twice So He Can Get Tons Of View & Subscribers And Also Profiting Off It And Also Faked His Donation
My Friend: Yeah i Agree
The suffering one experiences after spending hours in front of a computer watching YouTube videos.
A: Ughhh, I've got a headache.
T: Why, what's wrong?
A: I came down with Youtuberculosis today. I just couldn't stop watching videos online last night, and it kept me up.
T: Is that contagious?