Nixta Rolls

"So, Marissa ran an experiment where Google increased the number of search results to thirty. Traffic and revenue from Google searchers in the experimental group dropped by 20%. Ouch. Why? Why, when users had asked for this, did they seem to hate it? After a bit of looking, Marissa explained that they found an uncontrolled variable. The page with 10 results took .4 seconds to generate. The page with 30 results took .9 seconds. Half a second delay caused a 20% drop in traffic. Half a second delay killed user satisfaction. This conclusion may be surprising — people notice a half second delay? — but we had a similar experience at Amazon.com. In A/B tests, we tried delaying the page in increments of 100 milliseconds and found that even very small delays would result in substantial and costly drops in revenue."