I would agree that this is an excellent strategy for engaging your learner when used appropriately. The same tweeter pointed to references of social psychologists highlighting the use of one's name as a trigger for increased attention or focus. They call it "The Cocktail Party Effect". Certainly there is more to good design, and gaining learner attention (as Gagne suggests), than simply using someone's name. But when we are struggling to keep what little attention we have from our learners it's helpful to use every advantage and cognitive trick we can... even the little things.