No idea, but it used to cause confusion that on a British keyboard Shift-3 produced the £ symbol, but a US keyboard produced the # symbol - while in the respective countries they were both referred to as "pound"

Perhaps some British influence somewhere? Where were # tags first popularised in the public imagination? Twitter I assume? Or something else?

---

Edit to add side-observation:

"Octothorpe" I quite like, but I've never heard it spoken and mostly only read it in quite nerdy internetty contexts. Even amongst nerds I don't think we really use it that much.

Meanwhile @ is occasionally referred to as "commercial at" and I've seen one or two uses of "ampersat" for it. Again, I don't think I've ever heard anyone use those in speech even though they might actualy be useful for disambiguating the symbol from the word (but I think people say "at sign" when they want to be specific).

---

Another passing thought:

I remember being exceedingly irritated to get a Mac with a UK keyboard in the early 2000s and discovering that the # symbol was not shifted to another key (as on a PC keyboard) but had to be accessed via the Alt-gr key combo (possibly with shift thrown into the mix as well?) ... as a recovering C++ developer at that time it was super annoying.

Nowadays I have a Swedish keyboard and while # is fine, I have similar pain with {} and [] ... and now I think of it, what is the proper name for what I exclusively call "curly braces" ?