The official Pinterest engineering blog.

Marc Andreessen famously said that for startups, “the only thing that matters is getting to product/market fit.” Product/market fit means providing enough value to enough people that the startup can flourish. We believe the key to sustainable growth is putting Pinners first, and finding ways to increase the value people get from Pinterest. That could mean improving the experience for existing Pinners, more effectively communicating the benefit of Pinterest to new users, or improving content for less engaged people. With tens of millions of Pinners, though, it can be a challenge to understand if we’re reaching our goals.

We measure success with four techniques: user state transitions, Xd28s, cohort heat maps, and conversion funnels. This post covers how to understand these different types of metrics and how we use them to identify problem areas and inform our strategy and decision-making on the Growth Team.

Understanding gains and losses with user state transitions

The metric: For this metric we use a simple model, with three states to understand the growth of our service: Monthly Active Users (MAUs), dormant Pinners, and new Pinners that just joined. The chart monitors the number of people who go from one state to another on a daily basis.The sum of the four different transitions yields our Net MAU line, which shows the total number of additional MAUs we added that week.

Possible user state transitions are:

  • New signup: When a new person joins Pinterest
  • New -> Dormant: When a new Pinner doesn’t use Pinterest in the 28 days following sign up
  • MAU -> Dormant: Pinner was an MAU, but didn’t use Pinterest for 28 days.
  • Dormant -> MAU: Pinner used Pinterest after having been inactive for 28+days.

How we use it: This is one of the most important graphs for the Growth team because it tells us where to focus. By looking at where we’re losing Pinners, and where we’re gaining them, we can decide where to concentrate our efforts to deliver maximum impact. For instance, if we see an increase in the number of new Pinners transitioning to dormant, we know to focus our efforts on better communicating Pinterest’s value in the new user experience during the person’s first week.

Monitoring engagement through Xd28s

The metric: Xd28s are the number of Pinners who have used Pinterest X days in the past 28 days. For instance, 4d28s+ are the number of users that used Pinterest 4 or more days during the past 28.

How we use it: There are many ways people can use Pinterest, so there’s no one specific thing Pinners do to gain value. We use Xd28s as a proxy for the amount of value a person is getting from the service. We segment into three major categories: 14d28s+ are core Pinners who are deriving a lot of value; 4d28s+ are casual and getting some value, and anyone below 4d28 is a marginal Pinner who’s likely at risk of churning because they’re not receiving much value. By monitoring the ratio between the different groups, we can determine how much value people are getting and see how it changes over time. If one of the less desirable segments (such as marginal users or casual users) begin to increase, we can focus on understanding why that’s happening and determine what we can do to fix it.

Tracking new user retention with cohort heat maps

The metric: The cohort heat map shows the activity level for new Pinners; where red represents high activity and blue indicates low. The columns along the x-axis represent the day the person joined, and the rows along the y-axis represent the number of days since they joined. The coloring of a specific square in the graph represents what percentage of Pinners who joined on day X were subsequently active on day Y.

How we use it: The foundation for sustainable growth is retaining users. We use graphs like this to see how our new user retention curve changes over time. When the red and yellow extend further up a column, retention is improving. If the blue and green areas begin to decrease, a retention or new user activation problem has been introduced. In the mock example above, something happened around 2013-04-01 that hurt retention. This graph becomes especially powerful when segmented by gender or locale, which allows for easy identification of segments of the user base where retention can be improved. We can then monitor over time to see if retention is indeed improving.

Understanding Pinner interactions using conversion funnels

The metric: For multi-step flows, conversion funnels measure how many Pinners get to each step of the flow.

How we use it: We use conversion funnels for monitoring landing pages and sharing, invitation, and signup flows. By understanding how people are interacting with the feature and seeing where users are dropping off, we know where to focus our efforts on improving the flow. Sometimes the fix is functional: If someone tries to send a Pin to a friend, but can’t find the friend they are looking for, we can improve the friend recommendations or our typeahead logic. However, Pinners can also drop off in the flow because they don’t understand the value and don’t have enough motivation. At this point, we collaborate with the design team on creative ways to communicate that value. A great example is our current sign up walls on iOS and web, where we show use cases to communicate how people use Pinterest.

Putting Pinners first

As you can see, fixing retention issues can be as simple as reminding users what they may be missing out on, or as complicated as rethinking the user experience for a segment of the user base. For us, it always starts and ends with ensuring a great experience for new and existing Pinners. If challenges like this interest you, the Pinterest Growth team is hiring!

John Egan is an engineer on the Growth team.