[AnthonyMouse]

> The gap between creating something useful (an app) and the ability to sell or market it is HUGE. That gap is the difference between useful or not.

Most of that gap is the difference between making it and selling it. To sell it you need payment processing, customer service now that customers are paying and expect you to resolve their billing problems etc., marketing sufficient to get enough initial users to cover development costs now that you're trying to turn a profit, accounting and tax remittance now that you're taking money, etc.

That stuff isn't required if you make it for yourself and then post it on the internet for anyone else to use for free.