5. The method of claim 3 , wherein determining a measure of similarity between the plurality of social bookmarking tags and each fragment in the series of fragments of the web page comprises: determining a measure of similarity between the plurality of social bookmarking tags associated with the web page and a fragment in the series of fragments of the web page, wherein each social bookmarking tag in the plurality of social bookmarking tags comprises a text descriptor assigned by one or more users to the web page.
5. The method of claim 3 , wherein determining a measure of similarity between the plurality of social bookmarking tags and each fragment in the series of fragments of the web page comprises: determining a measure of similarity between the plurality of social bookmarking tags associated with the web page and a fragment in the series of fragments of the web page, wherein each social bookmarking tag in the plurality of social bookmarking tags comprises a text descriptor assigned by one or more users to the web page. 6. The method of claim 5 , wherein determining a measure of similarity between the plurality of social bookmarking tags associated with the web page and the fragment comprises: organizing the plurality of social bookmarking tags into unique pairs; obtaining related social bookmarking tags associated with each of the unique pairs to generate an expanded set of social bookmarking tags corresponding to each of the unique pairs; determining a measure of similarity between each expanded set of social bookmarking tags and the fragment to generate a similarity score for each of the unique pairs; and multiplying the similarity scores for each of the unique pairs together.