Opportunistic wireless content sharing via Mobile Ad hoc NETworks (MANETs) can increase throughput, lower latency, extend network coverage and reduce load on infrastructure. While the benefits of content diffusion clearly depend on the underlying movement dynamics and content demand, the impact of these factors on diffusion remains largely unexplored. We analyze content sharing potential based on device encounters inferred from a large multi-site wireless LAN trace. We explore the impact of time, location, and number of sources on diffusion, finding that contexts with higher activity generally promote faster diffusion, while additional content sources improve diffusion mainly in the short-term. We then apply real-world demand patterns from a popular campus maps application to content diffusion simulations. We find that up to 70% of map requests could theoretically be served from the peer network over the first 12 h. Finally, our analysis of the impact of trace uncertainties and individual device variation on diffusion potential reveals large differences based on the selected assumption and chosen source devices. We discuss these results and their implications for content-diffusion in MANETs.