What is the cloud, and where is my stuff?

The cloud is a comforting name for a plain fact: your files live on someone else's computers. Specifically, in data centers, warehouse-scale buildings full of servers operated by Amazon, Google, Microsoft, Apple, and a few others, and much of the internet you use daily runs on rented space in the same buildings.

Your photos are not floating anywhere. They sit on physical drives, usually copied across several machines and often several geographic regions, which is why cloud storage survives fires and spilled coffee that would kill a laptop. That redundancy is the actual product.

The trade-offs are real, though: you need internet to reach your things, you are trusting a company's security and its terms of service, and a free tier can change beneath you. The sane setup is cloud plus one local backup, so no single company or single drive holds your life alone.