The newsroom at washingtonpost.com, the website of The Washington Post , is not so different from that of a print newspaper, with one notable exception:  At a time when newsrooms across the country have empty desks from recent buyouts and layoffs, staff numbers here are expanding to fill every available nook and cranny. Washingtonpost.com, part of the publicly held Washington Post Company, is a success story in an industry where the divide between vibrant online ventures and shrinking print products is increasingly sharp. Although analysts have been studying this conjoined twin-like pairing — where one twin is thriving and the other is declining, but they both depend on each other for survival — there doesn’t seem to be any consensus yet on a number of key questions: Can online revenues replace print revenues? Does an unlimited “news hole” leave consumers drowning in content? Can a website whose main audience is national still dominate a local market?…