Temporal annotation is a research area that involves the identification and labeling of time-related information in text or multimedia data. This includes recognizing and marking temporal expressions such as dates, times, durations, and intervals, as well as identifying events and their temporal relations. Temporal annotation is important for various applications such as information retrieval, question answering, event detection, and summarization, as it enables systems to understand and reason about the temporal aspects of data. Researchers in this field develop algorithms and tools for automatically annotating temporal information in text and multimedia content.