I’ve stopped reading Jakob Nielsen on a regular basis, so I missed this: Top-10 Application-Design Mistakes. As it turns out, this is one of the few of Jakob’s Alertboxes that I agree with more than disagree with. Iterative design, paper prototypes, decide what your app should do, beware nonstandard GUI controls, design for the user rather than the back-end system, etc.
Number two particularly amuses me. I was on a business trip with someone who was bitten, hard, by this bug (on a different travel site). His boss booked his travel, and didn’t pay attention to the fact that the position of the months on the calendar changed between the Start and End date fields. Worse, the travel was in February in a non-leap year, so there wasn’t even a difference in date numbers to clue him in (since the Wednesday in March was exactly 28 days after the Wednesday in April). Result? A very long delay for our friend at McCarran Airport in Las Vegas trying to straighten the problem out, so that my friend could get back 30 days earlier than his ticket specified.
Usability mistakes cost.