Topic discovery, summary generation, automatic tagging, and search indexing for segments of a document

摘要

System and methods are disclosed for discovering topics in sub-segments of documents, and extracting terms from a sub-segment representing topics or summaries of the sub-segment, and displaying such terms in connection with the sub-segment or with the document, which can also function as automatically generated tags or labels for the segments or for the documents. Methods are also disclosed for building search indexes based on specific sub-segments of documents, such that, users can search for contents in a specific segment of the document. One embodiment of such a search index is with emails, blogs, and forum articles that typically contain segmented contents added at different times or by different authors in a format known as a thread, and searching in a specific segment such as the most recently added segment can help quickly find the most relevant information without repeating the same information in other segments in the thread.