Failure to convert stuff in a shopping cart on a website into a completed sale is tied to the quality of the site – I’ve seen reports of sites redesigning their shopping cart and checkout process and seeing 50% increases in their conversion rate.

What does this mean? It means their customers were having problems with the user interface of their prior cart.

If a web shopping cart was treated with the human interface guideline respect that a typical Windows application receives, then this would never have been a huge problem.

I’ve seen people try to use eBay and give up. It’s user interface sucks.

When a user fires up a new Windows application, chances are they already know how most of it works, and they only have to figure out the things that are unique to the work that this particular app does. They already know how to print, how to open a file, how to use the clipboard, and so on.

We’re moving from trying to make applications that users can feel comfortable with, to applications that users will think are cool. But cool doesn’t equal usable.

You’re a designer, so of course you’re happy about that. But will your users be?

On the other hand, at least with Avalon, keyboard access, accessibility, etc. works like Windows is supposed to. After all, consistency of behavior is more important than visual consistency.