"We put little weight on the idea. We ask mainly out of politeness. The kind of question on the application form that we really care about is the one where we ask what cool things you've made. If what you've made is version one of a promising startup, so much the better, but the main thing we care about is whether you're good at making things. Being lead developer of a popular open source project counts almost as much." - Paul Graham : "Want To Start A Startup?"

Ideas are a dime a dozen. Execution is the key. Rarely is your idea going to be a completely original one; and if it is a good one, be sure that someone else is probably thinking the same thing.

But you differentiate through execution. And really, execution is the hard part.

Being able to execute an idea is vital to a business, and if your business is made up of people that do more walking than talking, than you are on the right track. You can remain agile in idea and efficient in execution. But if your co-founders are the opposite, you might need to re-evaluate the arrangement.