orecast's iPhone app began as an experiment. Would it be fun to know where your friends were headed? To answer this question we set up a group chat and told our friends to only post where they were going next. We were surprised both by how much our friends engaged with this simple text based experiment and by how much fun we all had using it. So without writing a line of code or designing a single pixel we validated the basic premise of our app.

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n keeping with this lean approach we forced ourselves to release a new version of the app every week with the aim of testing a specific hypothesis. If whatever key metric we were testing for moved in the right direction we'd keep the change, otherwise we'd move on. After two months of this process we released version 1.0 of Forecast.