The increase in profit has been attributed to increasing ebook sales. HC's total ebook revenue increased by 30% over last year. eBooks made up 22% of overall book publishing revenues last quarter, up from 15% a year ago.
That 30% growth rate is worth noting because it tends to contradict the claims made by Nicholas Carr, Digital Book World, and others that the ebook market is flattening out. HarperCollins' data doesn't bear that out, and since pundits are working from (at best) incomplete data sets and/or estimates it would be a good idea to hold off on proclaiming the end of boom ebooks.