Paul Graham recently wrote that a “a startup founder is in effect an economic research scientist.” This is the way you should view your company. It’s an experiment. You’re trying to discover a product that will work for some market, while also being a hugely motivating space for you and your cofounders to work in for (potentially) ten years. What is that thing? It could be anything. You have to try a bunch of different ideas, until something sticks. No idea is sacred.
I can't say this enough to founders.