Let's start by level-setting expectations right away: this post has very little to do with actual SEO implementation. You won’t find any performance tips, analytics hacks, or war stories with technological terrors and the people who engineer them in this post. If that’s what you’re looking for, there are several othersources you can peruse.
In February 2011, a client I was working with ran global usability test in cooperation with Spotless Interactive in London, Hamburg and Oslo. One year later and the feedback from the usability tests are being implemented, which includes improvements to the booking engine, navigation menu, a url rewrite and a new home page.