That's the title of an article in the New Yorker by Atul Gawande--he considers the differeences between good ideas which spread fast (like anesthesia) and those which spread slowly (like aseptic methods). He uses the distinction in discussing a project to change the way Indian medical personnel handle newborn babies in one state. He cites the persistence of drug company salesmen, who visit doctors again and again, trying to set up a relationship of trust in order to persuade them to use a new drug. In his project, their representative visits a local hospital again and again, before finally getting the nurses to change their methods.
Gawande makes a reference to the role of agricultural extension in teaching farmers new methods in the 20th century. I did my first tweet (@facelessbureaucrat) to point out to him that Seaman Knapp, the father of extension, believed teaching was not the key; having a local farmer demonstrate the methods on his own farm was much more effective. I doubt I'll do much on Twitter, though it might be an outlet for my nitpicking, as in the one to Gawande.
I do wonder how much demonstrating extension does these days.