The experiment of providing "American Gods" for free over the net appears to have been a success.
"The Indies [ie. independent booksellers -- Neil] are the only sales channel where we have confidence that incremental sales were driven by this promotion. In the Bookscan data reported for Independents we see a marked increase in weekly sales across all of Neil’s books, not just American Gods during the time of the contest and promotion. Following the promotion, sales returned to pre-promotion levels. "
The complete article is
here (he doesn't begin with that topic, so browse a bit down)