Lukas Mathis on the mysterious Gmail checkbox-with-dropdown, and why empirical design is important:

“What Leggett described is exactly how I felt about the widget when I first saw it. I immediately figured out how to use it, but my gut reaction was «most people are not going to get how this works.» It seems I was wrong. This is one of the reasons why I don’t put too much trust into opinion-based usability reviews: There’s a lot of guesswork involved, and guessing how humans behave is an endeavor fraught with peril.”