Introduction: Opinion retrieval aims to tell if a document is positive, neutral or negative on a given topic. Opinion extraction further identifies the supportive and the non-supportive evidence of a document. To evaluate the performance of proposed technologies, a suitable corpus is necessary for opinionated tasks. This task includes the definitions of the annotations for opinionated materials. Heterogeneous experimental materials are annotated, and the agreements among annotators are analyzed. How human can monitor opinions of the whole is also examined in research papers. The annotated corpus can be employed to opinion extraction, opinion summarization, opinion tracking and opinion question answering.