question:  In the context of the article, who is Si and what does he do?
context: 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). Vanity Fair 's Graydon Carter might be there too, although he has transferred his main allegiance to a place called Patroon. Filling out the room are other editors, publicists, and writers from these magazines and GQ and House & Garden and so on. Some of the lesser fry may even utter the Condé Nast mantra--though it is hardly necessary at the Royalton--as they grab for the check: "Let Si get this." S.I. "Si" Newhouse Jr. and his younger brother, Donald, control Advance Publications, one of America's largest privately held companies. Donald tends to Advance's hugely profitable newspaper, radio, and TV holdings. Si runs the less profitable but more glamorous properties. The expense-account lunch is a hallowed journalistic tradition. It's a closed economy where almost all human needs and desires can be gratified with a miraculous, unlimited currency called the Si. The car, which costs $50 an hour, is written into your contract. No problem--you send your assistant to buy a pack for you. (Could be worse for the assistant: She could be forced to pick up her boss's birth-control pills, or her boss's pet from the vet, or presents for her boss's children--regular duties for Condé Nast underlings.) Si spends $20; you save a $1.50 late fee. But Si's generosity extends to even assistants and sub-sub-editors, dining on sushi at their desks. If you spend $10 or less on lunch, and claim you were working, Si pays. An editor at Allure says that "working lunches" there are limited to 10 a month. Si pays. After all, it's a "working snack."
output:  Si, or The Si, is the person responsible for covering the absurd expenditure of the Condé Nast magazines.
options:  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.