An anonymous reader writes: Facebook plans to nearly double in size in the next year. The social network announced plans on Friday to dramatically expand its NYC operations, adding a wealth of new engineers to enhance features and write fresh code for the website that links more than 800 million users worldwide. "We'll be adding thousands of employees in the next year," Facebook COO Cheryl Sandberg announced from the company's New York City offices on Friday. Facebook currently has about 3,000 employees in California, Sandberg said, but just 100 in its Big Apple facility — mainly marketing staff. The company plans to expand that Madison Avenue office by opening its first East Coast engineering office.