What does this "word" mean?

[MrsPepper]

I accept your apology, Snowthers. :/ Trust me, I'd never do that to anyone on MC, especially you. Actually, I'd never do that period.

 

[D'Snowth]

I accept your apology, Snowthers. :/ Trust me, I'd never do that to anyone on MC, especially you. Actually, I'd never do that period.

Kewl!

 

[chestermcdragon]

712 12 74 6r347327
(this is the greatest)
me and my bro are l337 freaks.

 

[Infinity Sirius]

Well Yvette Snowthie Person, sorry someone would do that to you. l33t is an online language that a lot of gamers and pale-faced (those who do not get out much) people use. It's becoming more mainstream and I find it alot in webcomics. Megatokyo is usually the one who is blamed for bring the infamous l33t to millions of people.