Updated from 4:38 p.m. ESTAmazon.com ( AMZN) doubled its fourth-quarter profit while lifting its full-year revenue projections above Wall Street estimates. The online retailing giant said net income grew 112% to $207 million, or 48 cents a share, from $98 million, or 23 cents a share, a year earlier. Revenue grew 42% to $5.67 billion from $3.99 billion. Excluding a $200 million favorable impact from year-over-year changes in foreign exchange rates throughout the quarter, sales grew 37%. Analysts surveyed by Thomson Financial were expecting earnings per share of 48 cents on revenue of $5.37 billion. "This quarter shoed accelerated sales growth and record operating profits," Amazon CEO Jeff Bezos said in a press release. For the first quarter, the company said it expects revenue between $3.95 billion and $4.15 billion. Analysts had forecast revenue of $3.92 billion. For the year, the company said it expects revenue between $18.75 billion and $19.75 billion, above the Street consensus estimate of $18.25 billion. Shares of Amazon fell nearly 4% in recent after-hours trading to $71.40. Amazon said that over 330,000 developed had signed up for its Amazon Web Services offerings -- which sells businesses computing and storage as a service--- up more than 30,000 from the quarter before. The company also said that a record number of customers signed up for its Prime service, which provides unlimited free-shipping, but it didn't disclose any specific numbers. North American sales grew 40% year over year to $3.08 billion. Excluding favorable currency rates, international sales grew 46% year over year to $2.59 billion. Worldwide media sales grew 33% year over year to $3.33 billion. Worldwide electronics and merchandise sales grew 58% year over year to $2.21 billion.