Yahoo!’s search results page used to have a truecolor PNG sprite and employed AlphaImageLoader to achieve the transparency (an older version of the sprite is still around if you’re curious). Replacing the truecolor PNG with a gracefully degrading PNG8 (discussed previously) decreased the pageload time by 50-100ms for the users of IE 5 and 6. 100ms may not seem like much, but for a page that loads under a second, it’s at least 10%. Also, according to an Amazon study, 100ms slower means 1% fewer sales (even for their content-heavy pages). Earning 1% more by just replacing an image doesn’t look like a bad deal at all.