I often find myself explaining the same things in real life and online, so I recently started writing technical blog posts.
This one is about why it was a mistake to call 1024 bytes a kilobyte. It's about a 20min read so thank you very much in advance if you find the time to read it.
A kilobyte (kB) is 1000 bytes, that's what the prefix kilo means. A kibibyte (KiB) is 1024 bytes (the "bi" in the prefix means base 2 or binary). People often confuse them, but they're similar enough for smaller units, 10^3 ~ 2^10.
Oh and at first, kilobyte was used for both amounts, which is why kibibytes were introduced to fix the confusion, which perhaps was a bit late anyway.