When you have an idea, you start by marketing and selling it to others to make it real, to execute on it.

Then you have a product or service, and you concentrate on selling and marketing it.

But even when you are selling your end product, you'd do better if you also market and "sell" the idea behind it.

Communicating your idea - what makes the end result of your product possible - as well, will help you sell the actual product.

Think about Southwest airlines. To sell seats on their airplanes, they communicated the idea behind how they operate: cheap, with limited routes, but fun.

Apple's sold the iPod by conveying the idea of quickly and cheaply buying music and having a massive number of songs in your pocket at all times.

The idea is how you achieve the desired result the product promises. It's worth including in your communications when selling your product.