Philosopher Zvi Biener (Western Michigan) writes:

This might be of modest interest to some. Google has just released a tool for viewing relative word frequencies in their database of scanned books (slightly more details on the exact subset of books can be found here). I inputted the names of the Top 10 Most Significant Philosophers of Science of the 20th-Century, as polled this October. This is the resulting chart.  Caution must be exercised, of course: this is a chart of full-name instances only, relying on the results of an imperfect OCR process, in books only, across all disciplines, etc., etc., etc. The dataset is available for those with spare time.

Besides the most obvious navel-gazing uses (like searching for you and your famous colleagues!), you can also chart certain philosophical fashions.  Relatively few philosophers today realize that Auguste Comte ("wasn't he a positivist?") was actually one of the cultural giants of the 19th-century–but his fading fortunes are well-revealed in a search of books between 1825 and 2000 in comparison to Kant, Hegel, and Spinoza.  Or consider the shifting levels of interest since 1925 in Ralph Barton Perry and Henry Sidgwick.  Or Hegel's fading influence in German scholarship during the 19th-century, only to recover in the 20th.  Or how prominent American philosophers compare to prominent scholars in other fields.  Have fun.

UPDATE:  Philosopher David Auerbach (North Carolina State) writes:  "Two important points about using the search.  The distortion introduced by it being only books is important, particularly since for most of the 20th century articles were where the action was.   Second, if one of your search terms has high frequency it can swamp the others; get rid of it and the scale shifts so that you can see the details of the less frequent ones."  The former point was certainly true in Anglophone philosophy for much of the 20th-century, though one would expect books to reflect the prominence of certain articles as well.

ANOTHER:  More Google weirdness.  (Thanks to C.E. Emmer for the pointer.)