San Francisco startup Instacart plans to be operating in 10 more cities by the end of 2014. Chicago is getting same-day delivery. "One of the main reasons why we launched in Chicago was because there was so much competition," said Apoorva Mehta, Instacart's founder and a former Amazon engineer. "Competition, to us, is a huge indicator that there is demand for a service like this. ... We saw this as a positive signal."