  With mobile shopping surging in popularity, people are spending ever more
money on digital purchases through their mobile devices and phones. However,
few large-scale studies of mobile shopping exist. In this paper we analyze a
large data set consisting of more than 776M digital purchases made on Apple
mobile devices that include songs, apps, and in-app purchases. We find that 61%
of all the spending is on in-app purchases and that the top 1% of users are
responsible for 59% of all the spending. These big spenders are more likely to
be male and older, and less likely to be from the US. We study how they adopt
and abandon individual app, and find that, after an initial phase of increased
daily spending, users gradually lose interest: the delay between their
purchases increases and the spending decreases with a sharp drop toward the
end. Finally, we model the in-app purchasing behavior in multiple steps: 1) we
model the time between purchases; 2) we train a classifier to predict whether
the user will make a purchase from a new app or continue purchasing from the
existing app; and 3) based on the outcome of the previous step, we attempt to
predict the exact app, new or existing, from which the next purchase will come.
The results yield new insights into spending habits in the mobile digital
marketplace.
