www.sterupdesign.com/dev/wordpress/plugins/plugin-organizer/faq/
WHY
Example 1: If you have a large number of plugins and don’t want them all to load for every page you can disable the unneeded plugins for each individual page. Or you can globally disable them and enable them for each post or page you will need them on.
Example 2: If you have plugins that conflict with eachother then you can disable the plugins that are conflicting for each indivdual post or page.
Example 3: If you have plugins that conflict with eachother then you can disable the plugins globally and activate them only on posts or pages where they will be used.
Note: If you are having troubles you can view the documentation by going to www.sterupdesign.com/dev/wordpress/plugins/plugin-organizer/documentation/
Selective
Go to the Plugin Organizer settings page and click the button under selective plugin loading to turn it on. Then visit your homepage. Finally return to the Plugin Organizer settings page and see if the button is still set to on. If it is not then you are running an old version of the MU component. Copy the PluginOrganizerMU.class.php file to the mu-plugins folder then deactivate and reactivate the plugin. Repeat these steps to ensure that the plugin is working. Remember that you will need to update the PluginOrganizerMU.class.php file whenever the plugin is updated and check your settings afterward.
PluginOrganizerMU.class.php
“IMPORTANT: To enable selective plugin loading you must move the /wp-content/plugins/plugin-organizer/lib/PluginOrganizerMU.class.php file to /wp-content/mu-plugins or wherever your mu-plugins folder is located. If the mu-plugins directory does not exist you can create it. The plugin will attempt to create this directory and move the file itself when activated. Depending on your file permissions it may not be successful.”
The mu-plugins folder contains “Must Use” plugins that are loaded before regular plugins. The mu is not related to WordPress MU. This was added to regular WordPress in 3.0 I believe. I only placed this one class in the MU folder because I wanted to have my plugin run as a normal plugin so it could be disabled if needed.
Disable a plugin on the front end and still have it enabled on the admin pages?
To load a plugin only in the admin you need to enable selective plugin loading for the admin areas and fuzzy url matching. Then globally disable the plugin you want to turn off on the front end. Next create a plugin filter with the permalink set to your admin url. Like www.sterupdesign.com/wp-admin/. Then enable the plugin for that plugin filter and select also affect children. Now the plugin should only be loaded in the admin.