One thing I'd like to do is angel investing in small companies. That's what's exciting, and if you are lucky to have a bit of money, you can take those risks.

There is a generation of skimmers. It's not that they don't want to read in-depth content, but they want to evaluate what the content is before they commit time. Especially on a mobile phone - you don't have the phone, or cellular data, or screen size to be reading full-length content.

Yahoo to me, as the founder of a company, is one of the biggest opportunities you could have; it's one of those classic Internet companies.

My first app was released in July or August of 2008. It was a 'fingermill' - a treadmill for your fingers. My level of programming was quite basic to begin with, so it was more gimmicky to start with. Day one it was up there, I had 79 pounds worth of revenue.

I don't feel like a different person. My motivation has always been to do technology apps and companies, not making money. Just because the money's come, nothing's changed.

I put together an iPhone app called TrimIt and released that in July 2011. About a month later, the private fund of the Hong Kong billionaire Li-Kashing cold emailed me and expressed an interest to invest, but they didn't realize I was 15. They thought it was a U.K. company with a team.

Be fearless and don't be afraid of failure. There is no better way to learn than through trial-and-error.