Apple demanded a 30 percent vigorish on all single-copy sales through its iTunes store. Profit margins in single-copy sales are thinner than 30 percent; publishers were thus paying Apple to move issues.

vigorish (n) 1: an exorbitant or unlawful rate of interest [syn: usury] 2: a percentage (of winnings or loot or profit) taken by an operator or gangster [syn: rake-off] – source: Why Publishers Don’t Like Apps