Plugins are composed of PHP scripts that extend and expand the functionality of WordPress.
They work by enhancing existing WordPress features or adding new features.
There are two types of plugins:
1. Regular plugins
These plugins are located in the “plugins” folder; They can be activated and deactivated on a per site basis inside the dashboard via the Plugins page in the Site Admin dashboard. They can be Network Activated or Network Deactivated via the Plugins page in the Network Admin dashboard on a WordPress multisite install.
When a plugin is Network Activated that plugin is automatically activated network-wide and is available for use on all sites across the network.
If a plugin is ‘Network Activated’ it no longer appears in the Site Admin dashboard at all. Only a Super Admin user is able to deactivate a ‘Network Activated’ plugin via the Plugins page in the Network Admin dashboard.
Stands for ‘must-use’ plugins. These are the plugins that are located in the “mu-plugins” folder. Any plugins placed in the mu-plugins folder are automatically activated network wide.
Refer to Installing mu-plugins for more information.
Regular plugins and mu-plugins are located in separate folders on your WordPress Multisite.
Your Default Plugins
WordPress comes with two default plugins installed:
- Akismet – a spam commenting service designed to reduce comment and pingback spam. It checks the content of a comment anonymously with an online server, to determine whether it is spam or not.
- Hello Dolly – adds a random lyric from “Hello, Dolly” to the top of your dashboard that changes as you navigate your admin panels
Things to know before installing plugins
While there are thousand of WordPress plugins most of these don’t work on WordPress Multisite sites and many have compatibility issues.
All WPMU DEV plugins are designed to be compatible with WordPress Multisite sites.
Make sure you check the plugin’s compatibility information before installing. The plugin may not have been updated for the version of WordPress you are using.
Plugins can be sourced through sites such as:
Whenever installing plugins on a WordPress Multisite install you should always:
- Check the plugin’s compatibility information before installing. The plugin may not have been updated for the version of WordPress you are using
- Thoroughly test each plugin (one at a time) by uploading it to your WordPress Multisite install and enabling it just for a test account using a default theme (Twenty Twelve).
- Activate the plugin on the test site, taking notes of any errors which occur. Re-test the plugin with the theme you plan to use (some plugins and themes can have comparability issues).
- Immediately remove any plugins with bugs using FTP and only use them network wide once you have fixed all of their issues
- Some plugins make changes to your database. Before installing any plugin that make dramatic changes, backup your database and files.
Important instructions when using WPMU DEV plugins
Most WPMU DEV plugins are now designed to be installed in the plugins folder.
Read carefully all of usage instructions for WPMU DEV plugins — some plugins involve uploading PHP files and folders to a range of different locations.
- Make sure you read these usage instructions carefully
- Some WPMU DEV plugins require additional steps to install and use
- If you don’t follow these instructions correctly the plugin won’t work and may cause problems with your installation