Somebody at Apple seems to be on a crusade against LCD subpixel antialiased font rendering. Recent versions of WebKit, included with Safari 5, introduced an unfortunate CSS option for web developers to override your preferred choice of text smoothing.
A setting of -webkit-font-smoothing: antialiased is now in Apple's global base.css file, effectively degrading text readability on all of Apple's web properties, including all of www.apple.com, the iTunes Store or the Mac App Store.
Thankfully, just as it is overriding your choice through CSS, Safari offers a mechanism to add your own CSS rules to have the final say. Create a plain text file with the following contents:
* { -webkit-font-smoothing: subpixel-antialiased; }
(Instead of subpixel-antialiased, you may also simply use auto, which is the default.)
Save it as a .css file, and you can enable it in Safari » Preferences » Advanced, in the Style sheet drop down.
That fixes the Apple website, and it turns out you could adopt the fix to iTunes and the Mac App Store as well, despite not having the option exposed in their Preferences windows. Read on to see how.
You'll have to open Terminal and simply copy these WebKit settings from Safari's plist to that of the other apps. Your only difference will be in the location of your user CSS file:
defaults read com.apple.safari WebKitUserStyleSheetLocationPreferenceKey
This outputs ~/Documents/user.css for me, as I called mine user.css and put the file in my ~/Documents folder. Having that, you can apply the same setting to the other apps, substituting your path for mine:
defaults write com.apple.iTunes WebKitUserStyleSheetEnabledPreferenceKey -bool true defaults write com.apple.iTunes WebKitUserStyleSheetLocationPreferenceKey "~/Documents/user.css" defaults write com.apple.appstore WebKitUserStyleSheetEnabledPreferenceKey -bool true defaults write com.apple.appstore WebKitUserStyleSheetLocationPreferenceKey "~/Documents/user.css"
Mac OS X Hints
http://hints.macworld.com/article.php?story=2011011804513148