David Roberts is a software engineering mentor who shares expertise on data management and user experience, particularly in React.js and Rails. He will be showcasing how to build a call center using AWS Lambda, React.js, and Twilio Lookup at SIGNAL. Jeff Sloyer, Developer Advocate for IBM's Bluemix, focuses on educating developers about utilizing Bluemix for various applications such as machine learning and video chats. Genevieve Nielsen, CTO of mRelief, aims to streamline social services by offering eligibility determination through accessible mediums like voice and text messaging, aiming to improve public assistance in the US.