When I ask Gareth Hickey to sum up his early days as a start-up founder, his response is both honest and instant: “Rejection. Lots of rejection.” Hickey was knocking on doors of publishers all over the world asking them to put audio versions of their journalistic content on his platform, Noa, in return for a revenue share. The trouble, however, was that the platform did not exist, and when most publishers heard the word audio, they assumed he was pitching a podcast. But Hickey, who was working at the time as an equity analyst with Susquehanna, persevered, and, along with…