What does unlisted mean? How does unlisted in the (Smart Contract??) work?

Also, how does Profile work? As in, how does it know to show you (the user) only your posts?

How does following work? How does the smart contract store who you are following? Is it possible to make other things unlisted, such as who you're following?

Lastly, how does deleting posts work? Does it just "de-link" the message from the UI?

Any resources or places to find out that anyone could point me towards would be appreciated. @TL