Netflix released its fiscal first quarter 2011 earnings on Monday and, thanks to record amounts spent on marketing, the firm reported an increase in net customer additions and a spike in revenues. The video subscription service added 3.3 million domestic net customers during the quarter, a 94% increase year-over-year — that service now serves 23.6 million subscribers globally. Netflix reported revenues of $719 million, up 46% year-over-year, and a net income of $60 million, an 88% jump from the same period a year ago. The company said noted that it expects DVD shipments to decline and spending on streaming content to “increase substantially” in the second quarter and beyond. Hit the jump for Netflix’s letter to shareholders.