Airlines continue to be a little slow to figure out the nuances of social media. You have to feel for them, in some ways. They’ve got enough going on without having to worry about Twitter and Facebook. But then again, Delta’s mistake yesterday was a pretty elementary one. In tweeting their congratulations to the U.S. soccer team on their World Cup victory, they posted a picture of a giraffe as a stand-in for Ghana. As a very simply Google search would have informed them, there are no giraffes in Ghana. Delta apologized for the tweet, and hopefully will brush up their flora and fauna for Team USA’s match against Portugal this Sunday …