Yahoo says it will close its offices from Christmas through New Year's to help save money. The cost-cutting move ends a year in which Yahoo's revenue declined for the first time since 2001. It's the first time that Yahoo has required most of its 13,200 employees to use vacation time or unpaid leave during the holidays. Only employees performing essential duties will be working from Dec. 25 through Jan. 1. Yahoo Inc., based in Sunnyvale, Calif., has eliminated about 2,000 jobs and shed other expenses since September 2008. The streamlining has helped offset a 12 percent decline in Yahoo's revenue through the first nine months of this year. Several other Silicon Valley companies traditionally close most of their offices during the holidays.