Yes, this is an annoying thing.

I'm a games programmer, and I have to take this into account when saving and loading games.

Say I'm saving the position of a player (10.7, 2.5)

If someone from Australia saves the position, it will use the '.' as the decimal point, but if someone from Spain saves the position, it will use the ',' as the decimal point.

And if you save/load the wrong one, it will crash :P

Most cultures use the '.' as a decimal place, and the ',' as a delimiter, and this is the Invariant Culture settings used to save/load games.