How do founders spot gaps in the market?

It was my problem, so I saw a need in the market. I was doing high level strategic insight work for Channel 4, Virgin, those kind of companies, and it was about the way that people, members of the public are engaged in consumer research and remunerated as well within that. So, what's their experience of taking part in research? And I thought, that looks broken to me. And I built tools in house at the agencies that I've been at before and I thought, I can build tools for this industry.