The writing may be on the wall for e-readers. In its quarterly earnings report today, Barnes & Noble said that holiday-period revenues for the Nook dropped 12.6 percent compared to the same time last year, topping out at $311 million. The book retailer also reported a Q3 earnings loss of $0.18 per share with revenue of $2.2 billion, down 8.8 percent from the same period last year. [Source: TechCrunch]