The concept of WordPress Multisite came into existence with the introduction of WordPress 3.0. For the first time, Mike Mullenweg, in collaboration with the large WordPress community, presented the idea of merging individual WordPress websites under a single WordPress account. The purpose of doing it was simple; to provide ease of access to people owning multiple domains on WordPress.
With WordPress multisite, managing and creating content for a number of websites becomes rather easy. With a single username and password account, you can now allow people limited access to organize and create content on directed domains so they can easily share settings, options, plugins, content, code, etc.
Importance Of Using Multisite
Assuming that you have a rather large network of websites to operate through and you want to merge the management to a single administration, then multisite has quite a lot to offer you.