Reader Steve Kreizl kindly called my attention to the "Academic Influence" website.  Even after reviewing their supposed "methodology," I can't figure out the results.   Whatever it is, it is not a ranking of influence in the field of philosophy (otherwise Saul Kripke and Timothy Williamson would not be runners-up for the top twenty-five).  It's also not exactly cross-disciplinary influence either, although that goes some distance towards explaining the list (e.g., David Chalmers, Daniel Dennett and Martha Nussbaum in the top ten).   It clearly gives a lot of weight to references in the popular media, the only way to explain, e.g., George Yancy being in the top ten (he has published extensively at the NYT blog, "The Stone").  Yancy ranks ahead of Joseph Raz and Charles Taylor, for example, who don't write for the NYT blog (nor do I needless to say).   Who, one wonders, is the audience for this?

The mysterious "top 25" below the fold:

1.  Sally Haslanger (MIT)

2.  Daniel Dennett (Tufts)

3.  Linda Martin Alcoff (Hunter College/CUNY)

4.  Martha Nussbaum (Chicago)

5.  David Chalmers (NYU)

6.  Jennifer Saul (Waterloo)

7.  Noam Chomsky (Arizona)

8.  Jurgen Habermas

9.  Robert Bernasconi (Penn State)

10. George Yancy (Emory)

11. Joseph Raz

12. Charles Taylor

13. Brian Leiter (Chicago)

14. Alain Badiou

15. Mpho Tshivhase (Preoria)

16. A.C. Grayling (New College of the Humanites)

17. Charles Mills (CUNY)

18. Patricia Churchland

19. Thomas Nagel

20. Anita Allen (Penn)

21. Peter Singer (Princeton/Monash)

22. Simon Schaffer (Cambridge)

23. Judith Butler (Berkeley)

24. Simon Critchley (New School)

25. John Cottingham

(For further amusement, try their ranking of the most influential philosophers of "all time".  The top five:  Kant, Nietzsche, Marx, Heidegger, Wittgenstein.  Less silly than the ranking of today's "most influential" philosophers.)

UPDATE:  Historian Anthony Grafton (Princeton) writes:    "Their list of historians who have been most influential since 1950 was interestingly cosmopolitan, with a fair number of the most important Germans. But David Irving came in at #31, and L. Sprague de Camp, if I recall, somewhat higher. Not altogether reliable, then."   That's an understatement!   Deborah Lipstadt was slightly behind David Irving, which is revealing.  On Twitter, the "Academic Influence" folks say the "method" involves looking at academic and media citations.  It is true that if you look at longer time periods, the results get less absurd.