The website mixes original journalism, celebrity gossip and high-class photography in a blog-like setting, under The Daily Beast title, borrowed from the fictional newspaper in the Evelyn Waugh novel 'Scoop'.
Its line-up of original content includes a piece on Europe's financial problems by Andrew Neil, chief executive of Press Holdings and former editor of The Sunday Times, called 'Bastard Americans'.
Brown described The Daily Beast as "a speedy smart edit of the web from the merciless point of view what interest the editors."
Politically speaking, the site will produce a non-partisan account of American news, commentary and culture, landing somewhere in between fellow news aggregator websites like the right-leaning Drudge Report and the pro-liberal Huffington Post.
Brown said: "We're hoping that if you like the sensibility The Daily Beast brings to choosing news and opinion then you'll trust us to be the lens you view it through."
The Daily Beast, backed by Barry Diller's InterActive Corp, will be Brown's first publishing venture since founding Talk magazine, which folded in 2001 after a three-year run.
Brown became editor of Conde Nast publication Tatler in 1979 before being named editor-in-chief of Vanity Fair in 1984. Eight years later she accepted the company's invitation to become editor of The New Yorker.
The Daily Beast is presently in soft launch mode, carrying no ads as it builds an audience.