The document discusses the concept of citizen sensing in the context of mining social signals and perceptions, emphasizing the role of semantics in enriching human experience and enabling effective data analysis. It covers various applications, tools, and frameworks developed over the years, including 'Twitris' for analyzing social media data, and highlights the significance of semantic models in processing user-generated content. The findings denote the explosive growth of data and the necessity for semantic scalability to derive meaningful insights for human activities and decision-making.