An interesting little case study that emphasises the value of testing a form before publishing it. In this instance, $12 million per year.
In this case Expedia looked at the data it was was collecting when transactions weren't going through. They identified a problem with an optional (and badly labelled) field.
I can't help but think that a little prototyping would have highlighted the problem before the form got anywhere near the website.
Expedia on how one extra data field can cost $12m