on 08-10-2012 05:43 PM
Although subjects of the crown and citizens of the United States supposedly speak the same language, there are some differences. Books are edited for the market they sell in (if written by an American author, it is edited for the UK -- United Kingdom -- market, and vice versa).
UK formats use the "King's English" (a guide to modern usage and grammar that sets the standard for writing in the UK) which readers in the United States would consider a bit strange. There are also often differences in sentence phrasing and in punctuation. For example:
colour > color
towards > toward
catalogue > catalog
See "Jane", see "John". > See "Jane," see "John."
Think of it like this: a book written in German by a German author needs to be translated into English to be sold here in the USA. It is also translated into King's English for the UK market (United Kingdom -- not just England, but all her territories: Canada, Australia, Great Britain, etc).
Essentially, UK format is edited to King's English standards and US format is for the United States readers. The story is the same but grammar, spelling, and puctuation are different.
If you are selling a UK format book, you need to be very specific about that in your description. Some people dislike them immensely, others of us really don't mind.