pictoral / figurative for the victory sign (or "v sign") and thus
1.) used in a similar meaning to owned
as a sign of victory (e.g. when defeating an opponent etc.)
2.) as an expression of great joy towards someone who just managed to solve a very difficult task or excel in a very important situation --> see w00t
(non-sarcastic) and related expressions
To emphasize the effect or enthusiasm, the letter can be repeated several times.