http://www.guardian.co.uk/books/interactive/2011/sep/23/books-power-100-interactive Genre, and SF/Fantasy in particular, are well represented:
#99 Amanda Hocking (YA vampire and zombie stories)
#96 Alan Moore
#81 Neil Gaiman
#61 Stephenie Meyer
#45 Salman Rushdie
#38 Philip Pullman
#28 Terry Pratchett
#18 The ghost of Stieg Larsson
#2 JK Rowling
Only 3 authors in the top 10, the rest are CEOs of either publishers or Net/Computer companies (Amazon and Google round out the top 3, with Tim Cook of Apple in #10). I noted 3 poets in the list.