https://geolua.com (On mobile it gives you a "consumer" view. Check it out on a desktop for a complete impression of what was possible)
I built a programmable and multiplayer capable way of doing geocaching. I keep it online because I still think it's neat, but back then I didn't think of any reasonable way to monetize or market it. It got some interest from the geocaching community, but IIRC links to it got banned from some geocaching forums because they wouldn't allow third party tools. ¯\_(ツ)_/¯
So I guess: 1) Think about what you build before you do. 2) Make sure the possibility to make money exists at all. 3) Don't rely on third parties. 4) Use what you've learned in your next project
I built a programmable and multiplayer capable way of doing geocaching. I keep it online because I still think it's neat, but back then I didn't think of any reasonable way to monetize or market it. It got some interest from the geocaching community, but IIRC links to it got banned from some geocaching forums because they wouldn't allow third party tools. ¯\_(ツ)_/¯
So I guess: 1) Think about what you build before you do. 2) Make sure the possibility to make money exists at all. 3) Don't rely on third parties. 4) Use what you've learned in your next project