Haven't looked at SSRN downloads in a couple of years, but here's the top ten US law professors by downloads in the last 12 months as of May 1:

1.  Cass Sunstein (Harvard) (28,599 downloads, 24 new papers)

2.  Dan Kahan (Yale) (18,796 downloads, 5 new papers)

3.  Daniel Solove (George Washington) (18,503 downloads, 2 new papers)

4.  Mark Lemley (Stanford) (14,973 downloads, 8 new papers)

5.  Lucian Bebchuk (Harvard) (13,940 downloads, 0 new papers)

6.  Orin Kerr (George Washington) (12,254 downloads, 4 new papers)

7.  Brian Leiter (Chicago) (12,097 downloads, 9 new papers)

8.  Bernard Black (Northwestern) (10,561 downloads, 5 new papers)

9.  Jeremy Waldron (NYU) (8,214 downloads, 6 new papers)

10. Tim Wu (Columbia) (8,158 downloads, 2 new papers)

And given how close to the top ten, I should note that my colleague Eric Posner had 8,065 downloads and six new papers in the last 12 months.

As the cases of Solove and Bebchuk show, "oldies but goodies" can keep the downloads pouring in!