What is Foursquare? Beautifully simple, at the outset:
- The (innovative, in terms of its mode) idea of a check-in - using my location-aware phone to say, "Guys, I'm here!"
- The (common) idea of a social network
- The (common) idea of user-generated content
- The (innovative, in this context) idea of gamification - challenges, badges, bragging rights
- An extended social group of people who'd like to help serendipity out in their social life
The developers and their friends found it worked for them. It added something in their social life, and was fun even when they didn't connect. And obviously they've pushed out in some new directions. But in terms of actively engaging business owners, that really didn't need to happen until much, much later.
I don't think the Foursquare team necessarily thought their idea was a business at all from the outset. Which is a pretty good way, in my view, to start out. When it was clear that there was potential to scale, it was also clear that there was a great investor pitch to turn a fun app into a true startup.
If you love an idea, have the skills, can spare the time and keep the costs way low, the give it a go, simply for the fun of it. Then, if you tinker but take it not much further, you've had fun and learned something. But who knows where it might lead!