Is there a list somewhere of which plugins need to be placed in the mu-plugins directory - and which do not?
Also - I read "These are activated by default, affecting all sites on a WordPress Multisite installation." Does this mean that I can place a 3rd party plugin in this folder and it will force use of it across the network as opposed to being an optional plugin?
Does this mean that I should place all plugins that are absolutely required to run the network - such as ProSites and and other network-related plugins in this folder?
I am having trouble understanding why this is necessary if we have the option to network activate plugins or not.