Google VP and de facto spokesperson Marissa Mayer is at the Web 2.0 Summit discussing "What Google secretly discovered along the way." Opens with a story about running studies about Google, doing split A/B testing (giving a small group of users a different version of Google — a different font, different buttons, whatever).
One test: Google tried adding more results to the front result page. Traffic dropped by 20%. (A "holy hell" kind of drop.) Marissa realized what was happening: Users getting 30 results instead of 10 were getting their results half a second later. "What users really wanted was, 'Give us more results in the same amount of time.' Speed is a huge component of what happens."
2:30: A Google search runs through many machines between the user query and the result page. The ISP, the index servers, load balancers. But all that happens in a quarter-second.
Google launched a "diet version" of Maps, much smaller and quicker-loading. Traffic jumped by two digits.
Instant feedback = steeper learning curve
Running results faster makes users become experts faster.
Google Video: Instead of instantly showing you your uploaded video, they showed an hourglass notice (rolling balls, actually). Upload traffic boomed when they switched to showing users their video.
Break up a big interaction into small, fast interactions.
This is also why Google Maps on mobile still doesn't really work.