About two days ago I wrote about changes in the way browser plugins are ging to be handled. At that time, based on the information I gathered from two threads on kfm-devel (linked to from the other blog entry), I assumed that the new Adobe Flash player plugin would just use XEmbed for the visual part but still be an old style in-process plugin with all its difficulties.
However, as we can read on Mike Melanson's blog today, the Linux version of the Flash plugin is now a native GTK application.
He doesn't give any details on how they communicate between the remainging plugin stub and the player application. Best guess is a Unix socket based custom protocol, though their current push to use non-ancient technologies would leave it as a possibility that their are actually using common technology like D-Bus.