See http://74.125.77.132/search?q=cache:olonKuXb1G4J:developer.apple.com/DOCUMENTATION/InternetWeb/Conceptual/WebKit_PluginProgTopic/WebKit_PluginProgTopic.pdf+

See http://74.125.77.132/search?q=cache:olonKuXb1G4J:developer.apple.com/DOCUMENTATION/InternetWeb/Conceptual/WebKit_PluginProgTopic/WebKit_PluginProgTopic.pdf+safari+plugin+architecture&hl=en&ct=clnk&cd=2&client=safari#9 http://74.125.77.132/search?q=cache:olonKuXb1G4J:developer.a... "WebKit–Based Plug-ins" This is how ClickToFlash works.