In the past three posts, I've introduced readers to Pirate Metrics, and shown how you can boost your acquisition strategy and activation numbers with Firebase products.

In this post, we're going to talk about one of the biggest problems majority of apps face: retention. The hard truth is that most people tend to only use a few applications every week, abandoning a majority of them after just a few tries. This might happen even if you did successfully activate a user.

The goal, for any product, is to become a habit for their users. And, for a person to pick up new habits, they need the help of triggers. The best products carefully use external triggers — things like push notifications, E-mailers — at appropriate times which help building habits.

For years, we have offered powerful tools to help you build these experiences: Google Cloud Messaging. Cloud Messaging is now a part of the Firebase suite of SDKs, becoming even more powerful than before.

The key capability added, thanks to this change, is something we call Firebase Notifications. By simply adding the required dependency to your application, you can now send push notifications to your users straight from the Firebase console. But that's not all: you can target the notification to a required segment. For example, you can inform those users who have shown an interest in a particular product that you have a deal running in your E-commerce application.

While quite useful, particularly considering how little you need to do to add them to your app, sending Push Notifications is a manual process and best utilized for campaigns. To truly improve your product, you need to first understand when you tend to lose your users, and build a system that helps you retain them.

The first part can be solved using the cohorts from Firebase Analytics. Cohorts help you visualise your retention by showing you what percentage of users do you retain over a period of time, broken down by days or weeks. Most of your users are typically lost in the first couple of days, which is usually an issue with your activation strategy. However, this decline tends to flatten out.

While you should certainly work on your activation strategy to help improve your cohort numbers on the first couple of days, you also want to look at some way to improve the numbers a little later, such as around days 5-7. One fairly straightforward solution is to build an automated system that sends push notifications using Firebase Cloud Messaging to these users approximately a week after they sign up. Using some kind of flag for "last used time", you could also ensure this notification is only shown to those users who are at risk of being dropped off.

You could utilize this strategy for things like extending trial periods for users who haven't used your product enough, giving yourself an extended opportunity to convert them into paying customers. Deals of any other form (either for E-commerce products or for in-app products) are other ways.

A carefully crafted strategy could play a critical role in your overall business. Do be mindful of avoiding a spammy notification system: you'll probably annoy your users and increase your uninstall count.

There are additional possibilities as well. Firebase Analytics tracks uninstalled users for you using the automated event "app_remove". As mentioned in the second post on acquisition, you can create an audience for users who have fired this event and retarget them using Adwords.

Also, using Firebase App Indexing in your application would help highlight content from your service in Google search results for your users. This is particularly useful during the early phases of the user's time with you when they haven't quite developed a habit of using your application directly.