Pokémon GO was a short lived mobile location-based gaming phenomenon. After its launch in July 2016, it quickly reached 500 million installs, but afterwards interest faded. As part of a large scale "in the wild" mobile phone study we have recorded phone usage and location measurements between June and September 2016. We investigate who were the people who installed and played Pokémon GO and what effects it had on their behaviour. We chose as a middle point the start of playing the game, and selected users that had activity for at least two weeks before and two weeks after it. In this work we present our findings on a sample of 2, 861 users. We compare demographic characteristics and Big Five personality traits of these users with 7, 904 non-playing users from the same time period. The general daily phone usage of players increased on average by 27 minutes, which represents 16% per day. In terms of large scale movement patterns, these did not change, with regard to diameter and total path length per day.

Tracking users across websites and apps is as desirable to the marketing industry as it is unalluring to users. The central challenge lies in identifying users from the perspective of different apps/sites. While there are methods to identify users via technical settings of their phones, these are prone to countermeasures. Yet, in this paper, we show that it is possible to differentiate users via their set of used apps, their app signature. To this end, we investigate the app usage of 46726 participants from the Menthal project. Even limiting our observation to the 500 globally most frequent apps results in unique signatures for 99.67% of users. Furthermore, even under this restriction, the average minimum Hamming distance to the closest other user is 25.93. Avoiding identification would thus require a massive change in the behavior of a user. Indeed, 99.4% of all users have unique usage patterns among the top 60 globally used apps. In contrast to previous work, this paper differentiates between users based on behavior instead of technical parameters. It thus opens an entirely new discussion regarding privacy.