People always told me photos have been done. My feeling was, these people are wrong.
Above all else, products spread when they're useful and they're usable
The best feature is less features.
You need to find people that are drawn to the idea that you build, and they end up taking it and making it even better.
I don't think you should ever start a business and move in a direction where you can't see it becoming a business.
Having a company that's successful is a wonderful platform to do new things. You don't have to raise money for it; you can take profits from the company and pump them into new business.