A lot of product questions are based on the idea of a user “session.” What do users do when they first log in? In what order do users take specific actions? How long do people use your site in an average sitting? Does activity vary by device?

A number of analytics tools define user sessions automatically. But, default definitions may not be appropriate for your unique product or, even if they are, there will be times you'll want to define sessions using your raw event data. This can seem daunting—but it doesn't need to be.

Our friends over at Segment recently came to us with a great idea: they wanted to get a bunch of analysts together to help a non-profit find insights in their data.

Watsi, a healthcare startup that's done an incredible job of building a donor community that supports healthcare for patients around the world, generously opened up their data to us. As we started collaborating with their team, we learned that they were looking to expand their community, patient support, and reach even further. They needed a repeatable model for increasing donations. They needed an engine.

Like so many startups, we set out in search of our own “aha moment.” What we found was that “aha moments” are less about advanced analytics and more about simple math and strong messaging.

Many leading tech companies have promoted “aha moments”—the instant a user understands the value of their product—as a key to growth. Most notably, Chamath Palihapitiya declared Facebook's “aha moment"—getting to 7 friends in 10 days—as Facebook's North Star on the path to 1 billion users. Twitter, Dropbox, and Zynga have all emphasized the importance of similar simple metrics and Slack, the current poster child for rapid growth, recently shared theirs.