Adjective. Referring to a person who updates their twitter, myspace, facebook, or forthcoming popular social network's status/mood/"what are you doing now?" with grandiloquent or high-sounding one liners regularly three or more times per day with the intention of directly advertising the ample size of their brain or indirectly indicating the emptiness of their being.
A twitty post looks something like: "Jackie realized that the money she spent on liquor in the last week could probably pay for the education of an African child. So, I guess, sorry Mwanajuma."
but is not limited to:
"Paul: The Spirit was OK - I wouldn't recommend paying full price for it. There will be some that love it. Just not me."