The Geoffrey Moore talk that Joel Spolsky said changed his business.
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They're also complementary to that, because Innovator's Dilemma is more about the strategy of building a product the right way to transform the market, while his books are about managing the market growth once you build the product.
Clayton Christensen gave a talk at Bell Labs not too long after his book hit the charts. The biggest take away of the talk was a bit different: Eat your own lunch before somebody else does. (He used the disk-drive industry as an example.)
Nice quote: "when VC give you money their only bet is that you will ride the tornado".