I keep a notebook in my pocket, and I write down all the stuff we could ever do with Foursquare.
Stop sketching and start building.
Building a product is easy. But building the company that builds the product is hard.
People can copy what you've done, but they can't copy what you still want to do.
I used to snowboard 30 days a year. Now its down to eight.
What we're starting to see is that the best apps tend to be the simplest, the easiest to use and the fastest to use.