Instacart's sustainability questioned as it rapidly expands, restructures deals with retailers
Farhad Manjoo / New York Times : Tweets: @fmanjoo Tweets: Farhad Manjoo / @fmanjoo : Retailers say that for now, paying @Instacart for new customers has been worth it. Me @nytimes http://www.nytimes.com/... http://twitter.com/...