Small note on the part about the price range UI controls: the author criticizes Amazon for using min, max number inputs rather than a slider control.

2 arguments against a slider:

1. Potentially it is much harder to make an accessible slider control. 2. Sliders break down when you have a distribution skewed away from normal. For instance, if 90% of results are in the range $0-$50, but then a few results are over $1000, how do you calibrate the slider? A naïve approach would render it almost unusable if you want to limit to products between $20 - $30. Otherwise you need some sort of logarithmic scale. I've not seen examples of this being done well.