Basking in the glow of a $15.7 million sale to Barnes & Noble, the founders of the e-book retailer Fictionwise revealed some impressive statistics today. Co-founder Stephen Pendergrast estimated that his eight-year-old company has sold around five million digital books.

Yesterday the bookselling giant Barnes & Noble announced that they had acquired the company. Fictionwise catalog includes between 60,000 and 65,000 titles, and Pendergrast noted that 500 new books are added each week.

Here’s more from the WSJ: “The single largest category is romance, which he said now accounts for 50% of all sales. He estimated total e-book sales in the U.S. at $100 million in 2008, although he said that some believe the market is larger.” (Via jafurtado)