Network Activate versus Activate by site/subsite

I recently stumbled upon an issue dealing with a Genesis specific plugin. I had network activated the plugin (as I’ve tried to do with all my plugins that I’m using on a MultiSite network), but it was causing the theme to behave incorrectly.

At the suggestion on Andrea at Genesis support, I Network Deactivated the plugin and then activated it individually on the main site and each subsite. From that point, it worked flawlessly. Andrea said that I should always activate ALL plugins at each site/subsite unless the plugin specifically states to Network Activate it.

I understand what she is telling me, but I’m rarely satisfied with just accepting something at face value. I like to understand the “why” of things because that usually helps me with other things in the future so I don’t have to ask so many questions with similar problems. Can anyone suggest a resource to help me understand the “why” of this as well as better understand when I should Network Activate and when I should individually activate a plugin.

Plus, I also note that there is a MU-Plugins directory that is for “must use plugins” to be installed into. From what I understand any plugin that I want to be required to be used on every site/subsite in the network should be FTP’d to that directory and they don’t have to be activated. Is my understanding of this correct.

I apologize if this should have been two posts, but I figured that since it was all related to plugins and their proper installation and activation that it would probably be O.K. in a single post. If you wish for me to break this out in to two posts, please let me know.

James Dunn

Athens, GA USA