1. Annoying friend or co-worker who fucks around on YouTube all day and replies to your e-mails with links to shit that's weird, not funny, or irrelevant.
2. That dude at the party who interrupts every conversation to tell you about some video he saw on YouTube that he thought was really awesome.
Example for 1:
Email to YTL friend:
"Hey what's up, I got the car tonight, so if you need a ride to the game, shoot me a text."
Email reply from YTL friend:
www dot random video link dot com
Exmaple for 2:
Guy at party: "...and so then all the people in the wedding just like, totally start dancing in the church!"
Girl at Party (to friend): "Ugh. There's all youtube losers here."
Other Girl: "I know, let's bail."