14. The system of claim 12 , wherein an existing topic text or subject text based on the content of a chronologically older segment in the document is displayed, wherein the portion of the content is displayed as a new topic text or new subject text to highlight the chronologically newer content in connection with the display of the existing topic text or subject text.
12. A computer system for discovering and presenting information in document segments, comprising: a computer processor configured to receive a portion of content extracted from a document segment, and to enable the display of the portion of the content in a display area, wherein the portion of the content is displayed as a tag text or label text of the document segment, wherein the tag or label text represents a topic or a summary of the document or a chronologically newer segment in the document, wherein the document contains multiple text segments, wherein at least two of the text segments are created by different persons, wherein the multiple segments are chronologically organized based on the time each segment is added to the document, wherein the type of document includes an email or forum discussion or blog or other documents in the format of a communication thread, wherein the portion of the content is identified and extracted by: (a) identifying the first chronological segment in the document, wherein the first chronological segment contains the content that is most recently added to the document by a specific person in the communication thread, wherein the content of the first chronological segment is a response to the content of a different segment in the document created by a different person at a different time, (b) dividing the document into a first part and a second part, wherein the first part comprises the first chronological segment, wherein the second part comprises the portion of the document that is not the first chronological segment, (c) extracting the content of the first part for analysis, (d) identifying a first term in the content of the first part, wherein the first term includes a word or phrase, (e) selecting the first term or a sentence or paragraph containing the first term, and (f) extracting the first term or the sentence or paragraph as the portion of the content.