"TextRank: Bringing Order Into Texts": http://belobog.si.umich.edu/clair/anthology/query.cgi?type=Paper&id=W04-3252
* graph based method for keyword extraction. nouns/adjectives as nodes, and co-occurences (within a window of 2-10 words) as edges. A x x B => there is a undirected link from A to B (vice-versa).
* graph based method to extract summary sentences. sentences as nodes. similarity between any two sentences is used as link weight.
* Unsupervised! yet obtain comparable performances to supervised method.
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Intuitively, TextRank works well because it does not only rely on the local context of a text unit (vertex),
but rather it takes into account information recursively drawn from the entire text (graph).
* "TextRank Java code": http://github.com/sharethis/textrank/tree/master