This is a major milestone for the dotcom age. The published books have been around for 200 years and Amazon is one of the pioneers in selling books over the web. They just announced that the first time e-Book sales have surpassed published books.
This also indicates that Apple’s timing of releasing the iPad is perfect at the market inflection point. Apple has already sold 3.3 Million iPads since its April 3rd launch date – thats apprx: 36000 iPads a day !
IMO – this is a significant shift towards a more widespread dotcom economy.