I saw an article referenced on the Wall Street Journal's webpage and found the analysis to be interesting (but that may be because I am a dork). Basically, they use the frequency each columnist uses specific, unique words and then apply that to individual columns to see if they can determine the author of the different columns.
I think the most interesting part was the list of the top words and adjectives/adverbs used by each author.
One of America's premiere literary minds dead at 71. link: http://edition.cnn.com/2004/SHOWBIZ/books/12/28/obit.sontag.ap/index.html Susan, we barely knew ye. R.I.P. [Edit]: I recently read her last book, Regarding the Pain of Others.