But one example is often markets where user behavior is fundamentally shifting, or where there is a sudden change (e.g. adoption of truly smart phones) leading

But one example is often markets where user behavior is fundamentally shifting, or where there is a sudden change (e.g. adoption of truly smart phones) leading to opportunity. Great point. A very good write-up on that is http://jasonlbaptiste.com/featured-articles/build-what-had-previously-not-been-possible/ http://jasonlbaptiste.com/featured-articles/build-what-had-p.... Maybe I will write a post on how to identify a great market, as that is a pretty big topic. For what it's worth, I'd love to see you write that.