Wau is a number from the infamous Vihart video. It is commonly known to equal one. In such video she mentions many ways to write it. She picked the letter di-gamma, or Wau because it sounded like Wow.

Wau is just Wau.

The phenomenon of having to come out as bisexual to the same person/people repeatedly because they assumed or hoped that your sexuality was a "phase." Refers less to the holiday and more to the 1993 Bill Murray comedy film in which the main character experiences the same day over and over.

The moment, when you don’t know how to answer to someone but you appreciate or agree with what the person said

short for "what about you?"
normally used on msn and facebook chat
could also mean "where are you?" or "who are you?" depending on the contex

A misspelling of the word, "Wow."
Used especially for especial disbelief.

What About you

wau
(verb)

to be in such a state of amazement where the only words that can be spoken is "wau (＾Ｏ＾)"