What is "willcall"

WillCall is a San Francisco-based startup company offering a mobile app for iPhone and Android devices that allows users to gain admission to live concerts, tip artists, and purchase merchandise during a show. It was named one of the Hottest Startups of 2013 by Forbes. Since its inception, the company has become known for editorial curation, a UX driven product strategy, and social networking integration. It has been called "an Uber for nightlife — one that makes everything from attending shows to buying drinks and merchandise much easier," by TechCrunch.