3. The method of claim 2 , where determining the indication of importance, to the particular document, of each of the one or more textual sequences, comprises: identifying, by a processor of one of the one or more computing devices, one or more pairs of the one or more textual sequences that occur within a paragraph of one another in the particular document; and estimating, by a processor of one of the one or more computing devices, an indication of importance of each of the one or more pairs relative to the particular document.
3. The method of claim 2 , where determining the indication of importance, to the particular document, of each of the one or more textual sequences, comprises: identifying, by a processor of one of the one or more computing devices, one or more pairs of the one or more textual sequences that occur within a paragraph of one another in the particular document; and estimating, by a processor of one of the one or more computing devices, an indication of importance of each of the one or more pairs relative to the particular document. 4. The method of claim 3 , where the indication of importance of each of the one or more pairs relative to the particular document is based on one or more of: a number of occurrences of each of the one or more pairs in the particular document, or depths of sentences, within the document, including the one or more pairs.