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.

That's why Google released Web Accelerator. "What's good for the Web is good for Google." (And vice versa, Marissa?)

This is also why Google Maps on mobile still doesn't really work.