Clear Channel is bringing its smart billboards to Europe (in the US they are active since 2016). They use anonymised mobile phone data to give advertisers better insights on where to place street billboards and follow up on consumer behaviour.
The company claims they will comply with GDPR standards and work only with data providers which do so and have consent from individuals. Still, it is tricky. It will be tough for people to deny their consent to data collection: they can only manage it at the level of each app terms of use for geolocalisation. Often this is a forced consent: without it, it is impossible to use the app. Moreover, research shows that in the 99,98% of cases re-identification after data anonymisation is possible.
a smartphone always on in our pockets, and no dashboard to go around the city at our terms.