Some very interesting advice:
Clayton [Christensen] contends that “products find a certain market only when they help their customers get done the jobs that they have already been trying to do.” [...] You say people aren’t switching from anything to use what you’ve built?
That means one of two things: either you don’t understand your product, or no one wants what you’re selling. Every product has competitors. Sometimes they’re other products and sometimes they’re human processes.
It's another way to phrase a common truth: people don't uncover new needs when they build new products, they find better ways to answer existing needs. The same is true for a product such as the iPad: nothing you can't already do with a computer, yet much better in a lot of ways.