One of the biggest that I know of is Gilt Groupe, founded by Michael Bryzek and Alexandria Wilkis Wilson. Many of the execs are also female. They're doing quite well, with revenues of apx $500mil in 2011. They do flash sales of apparel and the like.
Ms. Wilson's pedigree includes Phillips Exeter, Harvard (twice!), Merrill Lynch, and Louis Vuitton. That list says a lot about the NYC ecosystem. How many people with her background are going to make their way to SV to try a pure-tech play?