'wah gwan' means 'whats going on', taken from the carribean accent 'patois' and daily used as UK slang talk for hello, spelt as 'Wag1' on chat sites and MSN as it takes less time to type
Translates to "what's going on?" from wagwaan or wagwan. Means "what's up?" "what's happeningin your life?" or even just "hi, how are you?". Used as an internet slang greeting.