 In the context of the article, who is Si and what does he do?
Let Si Get This During a typical lunch time at the Royalton Hotel restaurant in midtown Manhattan, The New Yorker 's Tina Brown might be installed at her usual table, and Vogue 's Anna Wintour might be at her usual table (chewing on her usual meal--a $25 hamburger). S.I. "Si" Newhouse Jr. and his younger brother, Donald, control Advance Publications, one of America's largest privately held companies. It's a closed economy where almost all human needs and desires can be gratified with a miraculous, unlimited currency called the Si. If you spend $10 or less on lunch, and claim you were working, Si pays. Si pays.
 Si, or The Si, is the person responsible for covering the absurd expenditure of the Condé Nast magazines.
 Si, or The Si, is the person responsible for covering the absurd costs of of the New York Editor lifestyle.  Si, or The Si, is the person responsible for covering the absurd expenditure of New York parties.  Si, or The Si, is the person responsible for the culture that has developed around the writer/editor lifestyle.  Si, or The Si, is the person responsible for covering the absurd expenditure of the Condé Nast magazines.