It's hard to find a weak spot in Amazon's strong first quarter, in which total revenue rose 34%, to $13.18 billion. While net income fell 35%, to $130 million, earnings easily beat Wall Street expectations. Amazon gave lots of the credit to its digital offerings, saying nine of the top 10 selling products in the quarter were digital led by the Kindle Fire, the bestselling product in the period.

In North America, electronics and other general merchandise (home to Kindle) segment sales jumped 44%, to $4.78 billion, while media (home to books and e-books) sales rose a respectable 16%, to $2.2 billion. The gain in North America media was driven by Kindle Fire owners buying “ a lot of content, particularly in North America and we will add more content,” Amazon CFO Tom Szkutaz said. He wouldn’t comment on the impact of the Department of Justice antitrust lawsuit on the agency model, repeating that the decision will allow Amazon to lower prices on more e-book titles; e-book sales in the first quarter, he added, increased “very, very fast” in the first quarter. Overall, worldwide media sales rose 19% in the quarter, while egm increased 43%.

The company’s third party business had a very strong quarter, with unit sales up over 60%.

The bottomline was hurt by continued investment both domestically and overseas and Amazon has plans to open 13 fulfillment centers this year. Amazon is adding resources (people, technology, and infrastructure) in a large number of areas, Szkutak said, to keep fueling growth and to make sure Amazon has the right resources.

In his prepared remarks, CEO Jeff Bezos touted that Amazon now has 130,000 “in-copyright books that are exclusive to the Kindle store,” adding that 16 of its top 100 bestselling titles are only available through the Kindle store.

Responding to a question, Szkutak repeated that Amazon collects either sales tax or value added tax on about 50% of its sales.

Despite the big gain in sales and better than expected earnings, analysts pressed Szkutak to discuss when Amazon might begin to see margin improvement. Szkutak said he wasn’t prepared to talk beyond the provided guidance for the second quarter that puts sales rising between 20% and 34% with earnings ranging from a loss of $260 million to earnings of $40 million.