woot means whatever you want it to mean. You can also change the way it is being said. Usually people can connote it to happiness or "yay", but really it means anything.
1. woot! I got an A on that test!
2. Let's all go to the cafeteria. woot
3. I got my computer yesterday, woot woot
4. Life sucks. oh well woot
5. that is totally wooterz
6. wootz we're going to san francisco
Woot originated from a gaming slang term, and abbreviation of "We Owned the Other Team", owned meaning defeated decisively. abbreviated to "woot", zeros often replace o's to form w00t.