1. A method of automatically generating a summary for a textual document, comprising: receiving a segment type indicator from a user destined to receive an automatically generated summary, the segment type indicator indicating whether to segment a given textual document into one of word segments, sentence segments, and paragraph segments; segmenting the given textual document into a plurality of document segments based on the segment type indicator received from the user, wherein the document segments are one of words, sentences and paragraphs in the given textual document; extracting a number of document segments from the plurality of document segments to form an initial summary of the given textual document; for each document segment in the initial summary, calculating a set of correlation degrees between this document segment and its neighboring document segments that are outside of the initial summary, wherein the neighboring document segments of a given document segment refer to the document segments within a predefined distance from the given document segment; adding the neighboring document segments with higher correlation degrees into the initial summary of the given textual document; and creating a final summary of the given textual document that is to be displayed to the user based on the initial summary and the neighboring document segments that have been added to the initial summary.