The New York Times Company now has 668,000 paying digital subscribers across NYTimes.com, BostonGlobe.com, and Boston.com, an increase of 13 percent from the third quarter. The company also reported strong  full-year earnings, with a revenue increase of 5.2 percent even as ad revenues fell 3.1 percent year-over-year. Print ad revenue sunk 5.6 percent, but digital ad revenue rose 5.1 percent. [Source: The New York Times Company]