Where does slang come from?

Technology
Mouse potato - someone who spends all their time on the computer.
Phishing - stealing information through trickery
Blackberry prayer - the way people stand when they are holding their blackberry.


Teenagers 
Tool - someone who is stupid or geeky. "He's a right tool".
Buff - attractive."Wow, he is buff".
Innit - isn't it."it's well good, innit?