Today, mobile media play an increasingly important role as
ubiquitously available sources of information in informal learning
settings. This includes a growing number of mobile visitor guides
available at historical sites, botanical gardens, zoos or museums
(Schwan, Grajal, & Lewalter, 2014). Some of these visitor guides
come in form of predefined tours, typically offering walks focusing
on various different topics. Alternatively, mobile digital guides may
focus on individual exhibits,