Brent Simmons: The iOS App Store Brings Users Only Because It’s the Only Choice
This is a misconception that many people have — they think the App Store brings some kind of exceptional distribution and marketing that developers wouldn’t have on their own.
It’s just not true. It lacks even a grain of truth.
Build it (and upload it to the App Store) and they will not come.
Instead, you have to do marketing on your own, on the web and on social media, outside of the App Store. Just like always. The App Store brings nothing to the table.