It used to be that each company had it's own viscosity. ISO came up with standard ones. Each succesive viscosity is 50% more than the previous. 32,46,68,100,150,220,320, etc. You can still sell a 78 for example, but you can't call it ISO 78. It is 78 cSt at 40 C.
ISO was also responsible for the little snow flake for air conditioning, and the rest of the symbols on the dashboards of leter model cars.
They are trying to standardize shoe sizes and clothes, too.