Web data is a research concept and domain focusing on the systematic collection, analysis, and interpretation of information acquired from the World Wide Web. It investigates the structure, content, usage patterns, and dynamics of online information resources. Characterized by massive scale, inherent heterogeneity (including text, multimedia, and linked data), dynamic evolution, and complex interconnectedness, research into web data is significant for understanding information diffusion, online social phenomena, economic activity, and for developing methodologies in information retrieval, knowledge extraction, and large-scale data analysis.