There are a lot of cultural differences around the world and between individual countries of the western civilization. On which side of the road should I drive, how hot the weather is or perhaps most importantly - how big this beer is. The reaches of different measurement and interpretation are immense, so why should counting be any different.
How big is a billion? There are two different ways of naming big numbers, and they are called the Short scale and the Long scale. The long scale numerical system was used first, but in the 17th century, when traditional six-digit groups were split up into three-digit groups, short scale slowly came to use. Today, short scale numerical system is in use mainly in English speaking countries, while long scale is used in central Europe and around the world.
I personally prefer using the long scale, as it is mathematically more correct. Actually, I have no other choice, but it seems easy to represent something you were born into.
So what is the main difference? Long scale numerical system uses a word Billion to represent million millions or million square (1.000.0002 = 1.000.000.000.000), and a Trillion is a million to the power of three or million billions (1.000.0003). On the the other hand, short scale uses "one more" for every new term greater than million. In this case, Billion represents thousand millions (1.000.000.000), Trilion is a million millions (1.000.000.000.000) etc., so yup, billion equals trillion.
It's an interesting world we live in. And different date formats are a pain in the ass for software developers.