What is plugin-container.exe Process

Firefox 3.6.4 has a new feature plugin-container.exe in order to prevent Firefox crashes caused by installed plugins.
Here is the official explanation from Mozilla Firefox.

Firefox 3.6.4 provides uninterrupted browsing for Windows and Linux users when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins.
If a plugin crashes or freezes, it will not affect the rest of Firefox. You will be able to reload the page to restart the plugin and try again.

With the increased number of plugins with different useful functionalities, web browser users are willing to download and install web browser plugins for Firefox.

Although right Firefox is able to run plugin-container.exe only in Windows and Linux, it will probably add additional operating systems for this new feature.
The current configuration for the plug-in container isolates the processes for Adobe Flash, Apple Quicktime and Microsoft Silverlight plugins from the main Firefox browser process, preventing a crash to effect other processes.
So although the related plugin causes the covering Firefox tab to crash, it will not cause the whole Firefox browser to crash.

Firefox will soon add more plugins that will be controlled by plugin-container.exe and make Firefox more stable for web browser users.

If you had a Firefox plugin-container.exe crash on your computer's web browser, you can refer to related article.