Admittedly off-topic: I find Gladwell over-rated. He picks interesting questions to ask, all right, but he never gets around to answering them. Like: why does the tipping point work? He proposes no hypotheses.
For instance in Blink, he points out that a very successful golf player doesn't even seem to understand the reasons for his success. This has important implications. Do successful people really know why they are successful ? Do we take them a little too seriously ? After all self-improvement is big business.