WordPress Multisite (WordPress MS) is a special configuration built into the current version of WordPress that allows a self-hosted user to manage multiple WordPress sites on one network.
The multiple site version of WordPress is something to think about when an organization or person has several sites at once that run under one umbrella.
Development of WordPress Multisite
WordPress Multisite is a network collection of shared WordPress installations meaning, you can share plugins and themes on any of your sites. Originally called WordPressMU for WordPress Multi-user, WordPress MS creates a single installation of WordPress to support multiple sites in their own directories on a server. Each site has a separate directory for media uploads and their own set of tables in the database.
Prior to July 2010, WordPressMU was a separate version of WordPress. In WordPress 3.0, it was merged into the core and activation takes a couple of clicks, and some technical expertise, to change the single site installation of WordPress into a multi-site install.
On WordPress, the Multisite feature is available to enable multiple blogs and sites access to components under one user. A user can make a blog about one thing and another about something else, same with making a site or several sites.
Websites Using WordPress Multisite
WordPress.com is the world’s largest example of WordPress MS, featuring millions of WordPress sites on a single installation of WordPress.
Other examples of sites using the WordPress Multisite installation based from the WordPress Showcase on WordPress.org.
Glen Urquhart School, a school in Massachusetts uses WordPress Multisite. The teachers have their own sites as sub-domains. This allows class pages that show what’s going on and uses several plugins as an advantage towards the individual class discussion.
BBC America, a site of all the BBC American shows uses WordPress Multisite. Each sub-site has a child theme powered by a main framework. Child themes are themes you can make changes to within the code to have the site look like you want it to. This is the safest, easiest way to make any changes without affecting the parent theme on a self hosted network.
Best Buy, the largest specialty consumer retail electronics store, uses WordPress Multisite. They use Multisite to enable more than 1500 store associates to blog about relevant store information.