The first part of definition two. Think visually.
Which vowel does 3 look more like? o's are generally represented by zero, particularly if there's a diagonal slash through it in the given font.
A 4 is generally an A. 1's are very versatile, though. They're used as L's, T's, I's, and sometimes J's.
Leet speak - elite speak ???
promise last question :]
Yup, that's the meaning. I've also seen it done with a few other inserts: 1337 5p34k, and similar. Personally, I think that's going a bit overboard. I don't use it myself, though, so I'm not that worried about it.
Heh, and don't sound apologetic about it, like at the end there. I like bantering semantics.
"like ya know"?
Great, I've just turned Alexa into a 12 year-old valley girl. :-D
Yup, we had valley girls back in the 80's. :-D
If I get to play pretend, I'll imagine you're around 20 or so. 18 works, for legal reasons, but most 18 and 19 year-olds are still in the silly, high-school phase. You need a few years for most of them to get that knocked out of their system.
Raleigh, NC here.