The company gained 480,000 new customers between Sept. 30 and Dec. 11. Netflix has had a stellar fourth quarter as famlies turn to movies to avoid the gloom of the recession. Netflix also got a helping hand from Microsoft Corp., which promoted Netflix’s Internet streaming service in ads for its XBox 360. The video game console is one of several devices that bring Netflix’s streaming service to television screens. Netflix’s stock price dipped 3 percent in the fourth quarter, but still ended up 12 percent for the entire year.