It reminds me of an article on the latest issue of phrack, (Similarities for Fun & Profit, http://phrack.org/issues/68/15.html#article http://phrack.org/issues/

It reminds me of an article on the latest issue of phrack, (Similarities for Fun & Profit, http://phrack.org/issues/68/15.html#article http://phrack.org/issues/68/15.html#article ) Research in this area could trace back to the early days of information retrieval (such as tf-idf, http://en.wikipedia.org/wiki/Tf%E2%80%93idf http://en.wikipedia.org/wiki/Tf%E2%80%93idf). I am not quite familiar with the recent progress in this area, perhaps anyone could provide some pointers?