Can someone tell me what 'leet speak' is?

[Steve]

_b1cyNigny8

GYPO??? (http://www.urbandictionary.com/define.php?term=gypo)

[Stick]

HAHA! "Potentially dangerous code designed to keep parents in the dark!"

Wow, I love how parents think everything is about them.

[Steve]

N0 d0ubt.

Sorry, I meant 'no doubt'.

[ICY]

What if the terrorists start using it!? IT'S UNBREAKABLE!!!!!!!!!!!!