I can answer at least two of these...

"teh" is pronounced just as it looks, and means "the" but as in "the ultimate example of", like "teh cool" means "it's a very cool thing". It's Internet-speak. l337speak and lolspeak are both online distortions of spelling that include deliberate or common misspellings as a sort of visual dialect... l337speak users are pretending to sound like hackers, and lolspeak users are pretending to sound cute. Both are mocked by other Internet users. l337speak, pronounced leetspeak, uses numbers for letters and is more abusive-- "ph3ar my l337 haxx0r sk1llz, n00b" (fear my elite hacker skills, you newbie). Lolspeak uses cutesy but horrible grammar and is often used as captions for cute cat pictures. "I can has world dominashun?" Both l337speak and lolspeak use "teh" as a way of calling attention and emphasis to the noun it modifies.

I don't know where "woot" or "w00t" came from, but I think it's also l337speak in origin and it means "woohoo" or "yay".

Also worth noting in this dialect is "pwned", which is a misspelling of "owned" and pronounced "poned" (long o, not pawned). It means that you have been thoroughly conquered, either by losing to someone in a game or by being verbally smacked down. If you are in an online gaming setting, it's a pretty harsh "in your face". But elsewhere online, it's not meant as meanly, and can just be "ooo, you got a good pun in on her" or "haha, he totally stole your cookie when you weren't looking" sort of thing.

This Internet lesson was brought to you by the letter Y and the number 7.