Many of the best products we use today started as fun experiments, often peripheral to the team's main focus. Slack started as a browser game - the game failed, but the internal messenger grew to become a $27B company. Facebook began as a quirky (controversial) experiment at college that evolved to revolutionize our entire social world. Across so many successful startups, experimentation and play leads founders to uncover PMF. When Glitch failed to gain a sustainable audience, the team realiz...