I think the answer will depend on a clear definition of your goals, such as your revenue goals, how you see people using your software (and what you want to all

I think the answer will depend on a clear definition of your goals, such as your revenue goals, how you see people using your software (and what you want to allow them to do with it) and exit strategy. You may just want to build a good API to make it easy for hackers to customize and extend if you decide not to release the source.