Some high traffic sites conducted research and uncovered the following:
- Google.com: +500 ms (speed decrease) -> -20% traffic loss [1]
- Yahoo.com: +400 ms (speed decrease) -> -5-9% full-page traffic loss (visitor left before the page finished loading) [2]
- Amazon.com: +100 ms (speed decrease) -> -1% sales loss [1]
[1] http://home.blarg.net/~glinden/StanfordDataMining.2006-11-29.ppt
[2] http://www.slideshare.net/stoyan/yslow-20-presentation