On March 6, 1912, the oreo was born. And Nabisco indulged in some pretty wonderful social media recently to kick-off the 100th b-day celebrations. Oreo launched a lively game of #oreopinata on Twitter: every tweet using the #oreopinata hashtag constituted another thwack on the vitual papier maché. At seemingly random points in the day, the pinata burst open, sending a …