Mobile game players are picky: up to ⅔ of them will ditch a game after 24 hours. The flipside is that when players finally find a game worth recommending, they won’t hesitate to invite friends.
Viral growth is a big win for developers, who are faced with few channels for organic growth and high user acquisition costs. Here’s a quick guide to how viral growth works.
Step 1: find the viral feature
While some games become huge by word-of-mouth, like the notorious Flappy Bird, the term “viral” is usually reserved for games with built-in features for sharing. Think Crossy Road, with its shareable photo snaps of cute animals getting hit by cars and trains.
Other viral campaigns are built around the “core loop” of a game. In the core loop the developer creates need for something: gold coins, for instance. The player is then offered coins to invite friends, and in the last step of the loop, rewarded their coins for a successful invite.
But every successful viral campaign starts with winning over the user with a fun, high-quality game. Funplus studio lead Mikhail Katkoff sums it up nicely: “Follow a very simple approach when it comes to social features. Start off by giving your players time to play the game by themselves. Let them learn, enjoy it and have fun, then allow them to turn social.”
Step 2: learn to calculate virality
If you’re aiming for virality, you’ll likely need to optimize features, which in turns means knowing how your social features are performing. Your viral growth is measured as “K-Factor”, or the number of new referrals caused by a single player.
At its simplest, you only need two variables to measure your app’s K-Factor: the number of invites sent by each user, and the percentage of invites that convert into new users. These variables are commonly represented as:
i = number of invites sent by each new user
c = percentage of invites that convert
K-factor = (c*i)
Here’s a sample of how the K-Factor works over several cycles from Anil Das Gupta, product lead over at Natural Motion. The cycle here is defined as the time it’ll take for a loop to run its course (play—>invite—>convert). The table starts with 10 users, who each send 10 invites, with 5 percent conversion.
At the end of 10 cycles (which may span days, or even weeks, depending on how engaged a player is) you’ve got 10 more players from viral, in-app growth. Note that the percentage converted tapers off after a while, simply because users don’t like annoying friends by sending continuous invites.
Step 3: set up your measurements
To calculate K-Factor, you’ll need to track invites sent and the users coming in from those invites. If you’ve convinced your players to use Twitter or Facebook for invites this could be simple: each participant in the viral exchange has a username that can be tracked.
Tenjin’s attribution capabilities take care of most other cases. Attribution is an important step -- if you can’t see where users are coming from, you won’t be able to make strategic decisions around these features.
With measurements and calculation in place, you can use changes in K-Factor to evaluate whether your viral loop or sharing mechanic works or not. A decent K-Factor also factors into your lifetime value (LTV), effectively increasing the value an acquired user brings by using them to find yet more users. For developers challenged by high CPI, the tradeoff of time is a worthwhile investment.