JK Rowling sold $1.6m worth of eBooks in the first 3 days on sale

"Harry Potter fan site Pottermore sold more than $1.59 million worth of ebooks in the first three days after the books became available, Pottermore CEO Charlie Redmayne said on a Radio Litopia show, “The Naked Book.”
The sales were “considerably higher than I expected,” said Redmayne.
The ebooks, which cost $8 to $11.10 ($61.70 for the entire collection), can only be bought at Pottermore. Digital versions of the highly popular series were originally slated for an October 2011 launch, but the date was delayed as Pottermore (which is still in beta) was struggling to cope with overwhelming user traffic."

Source:  Mashable, 5th April 2012