The multi-user (MU) feature has been rolled into core as Multisite ever since Version 3.0.

It is ideal for a central system administrator to set up a large network of blogs with one installation. (The sites in this network have separate URLs which forward to the subsites.)

Individual site administrators are able to securely manage their templates and settings without affecting the other users.

Another Scenario: Web Developer has all the themes & plugins at the ready to create a new website for a client. They create the client’s website as a subsite, and then transfer all of the content to the client’s own base of operations.

Migrate a Subsite to a Single Site Using the Export Function

1. Export the subsite from the Multisite Network. This creates an XML file.
2. Install WordPress as a new Single Site Domain for the client.
3. Download and activate the free WordPress Importer plugin from wordpress.org.
4. Import the XML file to the new client’s domain.

wpmayor.com/how-to-migrate-wordpress-multisite-subsite-to-single-site

1. Add one line to wp-config.php
2. Login again – follow instructions
3. Add six more lines to wp-config.php
4. Create/update the hidden .htaccess file containing the rewrite code

1) Add one line to wp-config.php

define( 'WP_ALLOW_MULTISITE', true );

2) Login again – follow instructions

Example Sub-Domain: virgin.zapmap.com

 links to same as

Example Sub-Directory: zapmap.com/virgin

Note: Install WordPress in the root of your webpath if you want to use a sub-domain install. A sub-directory install creates a path-based network, even though it does not use file system directories.

3) Add six more lines to wp-config.php

4) Create/update the hidden .htaccess file containing the rewrite code

httpd.apache.org/docs/current/mod/mod_rewrite.html