If you haven't seen this article yet, it's worth a read. Depressing yes, but lays out how Amazon has influenced publishing in clear terms. I knew they were a threat to brick and mortar booksellers, we all know that, but I didn't realize to what degree.
On a side note, the article says there are a mere 1500 independent booksellers left in this country. So finite! That just makes me want to cry.