A few come to mind: learning the ways of the lean startup, coming up with hypothesis and metrics, learning about traction, boostraping, who's who in the Angel & VC game and build the network, other funding sources, opportunities and RFPs, investigate monetizing options and payment processors; finding the visionary early adopters, interviewing and keeping in touch with those, investigate the competition and their execution of the idea, contribute to build the vision and philosophy, manage the project (deadlines, resources, priorities), it's a never-ending list, don't even need to throw clerical work on it to make it so...