Def. 1-to express extreme glee with oneself, others, or several people through a text message.
Def 2-to end an annoying conversation with anyone by yelling out something random to scare them away.
Ex 1: Dude 1: What did you get for Crhistmas?
Dude 2: I got 300 bucks and a PS3.
Dude 1: Yayblez!
Ex 2:Random Guy: Yeah, so I was pwn'in some newbs on x-box live the other day and he got on my nerves even more so I jumped up and..(is cut off midsentence.
Random Guy 2: Yayblez!
Random Guy walks away.