[BlueSlide]

For possible financial gain: Web applications. Lots of them, most will fail as with mobile apps, but say I could do one every month or two, that's 12-24x the amount of chance of success than building one substantial well thought through, maybe unsellable thing.

None financial: I'd like to build robot or a virtual personal assistant (see film 'Her')

[riku_iki]

I think success is more dependent on marketing/promotion effort, than number of apps you would build.