We envision that future public display networks will be more interactive and open to applications from third parties similar to what we already have with smartphones. This paper investigates the application landscape for interactive public displays aiming to understand what would be the design and usage space for this type of applications. In particular, we explore people's perceptions and expectations regarding the diversity of applications that may emerge in future application ecosystems for public displays. We have devised a research methodology anchored on what is currently the rich and diverse range of applications in the mobile application market. We used a set of 75 mobile applications from Google Play application store and asked 72 participants about their relevance for public displays. The results showed that people had a clear preference for applications that disseminate content, and also that these preferences are affected by the type of location where the displays are deployed. These insights improve the understanding of the variables that may affect diversity in future display application ecosystems and inform the development of potential app stores in this context.