I am 54 years old, with no children.
Is there a reason I *should* know about Minecraft?!
Having seen JFKimberly's video, I think I've seen enough to know it's not for me. But at least I now know it's a computer game!
My husband and I are in our late-30s and early-40s and we don't have children.
Our videos are different to what most Minecraft videos are. We invent things and then share the inventions with others. Most Minecraft videos are just the kids's characters running around screaming. Or some YouTubers use it as a vlogging platform, where they're in the virtual Minecraft world, but then they just talk about stuff while maybe building something.
Minecraft is kind of like Lego, but instead of various-sized bricks, you have blocks that are all exactly the same size (1/2 your character's height), that you can place to build whatever you want. Most blocks are just aesthetic (textured to look like dirt, grass, stone, glass, quartz, etc.), but some are functional, like pistons and lights.
Really, there are many different ways to "play Minecraft." Some people build contraptions, like my husband and I do. Some people build massive, detailed structures (Starship Enterprise?), and some people don't focus on building but instead play "survival" type games. Oh, did I mention there are zombies?
As to the advertising, it's all done by YouTube/Google. We just tick the box that says "monetize", make sure all the content in our video is our own or free license (for copyright reasons), and then Google determines which ads get shown, and we get a percentage of the ad revenue applied to our account. Once we have a certain minimum balance, they issue payment.