I own a copy of American Gods, of course, so it's redundant for me. Nevertheless, it's extremely cool because, hey, let's face it: it's free stuff. And it exposes more people to Neil Gaiman and one of his wonderful novels.
So, as the Sirius Cybernetics Corporation says, Share and Enjoy!™
Update (2011): People keep finding this post somehow. I suspect they are googling for "read American Gods for free" or something of that sort, to which I say: dude, local library. Book piracy is dumb. Anyway, I keep getting comments saying, "It's not the whole book! It's just an excerpt!" This blog post was written in 2008. The entire book was available, back in 2008, and then after a certain amount of time, they removed the entire book and replaced it with an excerpt. Deal with it.