This definition arose from the infamous Youtube between two battle rappers ENJ & NIKS. The guy who got punched in the face proclaimed, before he got dropped "Oh you mad cus im stylin' on you", hence forth it has been a powerful movement.
Some people claim it was first used by Biggie however, in the 21st century, it will always known as this.
An absolutely foolproof way to keep minors from viewing content deemed "too mature" for them to watch.
Billy: "So I was trying to watch some videos for an M rated game, and I ran into an age gate, so I put in my real birthday. SOMEHOW it managed to figure out that I am 12. CURSE YOU AGE GATE!!!"
Bill: "Fucking age gate! *quick scroll* THERE! I was born on January 1, 1904. Fuck you age gate."