Universidad Carlos III de Madrid (UC3M) and the IMDEA Networks Institute, in collaboration with the International Computer Science Institute (ICSI) at Berkeley (USA) and Stony Brook University of New York (USA), have carried out a study that encompasses 82,000 pre-installed apps in more than 1,700 devices manufactured by 214 brands, revealing the existence of a complex ecosystem of manufacturers, mobile operators, app developers and providers, with a wide network of relationships between them. This includes specialized organizations in user monitoring and tracking and in providing Internet advertising. Many of the pre-installed apps facilitate access to privileged data and resources, without the average user being aware of their presence or being able to uninstall them.