CHICAGO (MarketWatch) -- Netflix Inc. NFLX, +1.32% said Monday that its third-quarter profit rose 63% on a 42% increase in subscribers to its video rental services, topping most analyst estimates. The stock plunged 16% in after-hours trading, however, as the company's fourth-quarter earnings and revenue forecasts fell far short of Wall Street's expectations. Netflix also plans to double the total amount spent on content in 2012, about on par with Time Warner Inc.'s TWX, HBO unit. Netflix said it earned $62 million, or $1.16 cents a share, compared with a profit of $38 million, or 70 cents a share, in the year-ago period. Revenue rose 49% to $822 million. Analysts polled by FactSet Research were expecting a profit of 96 cents a share on revenue of $812.5 million.