Multisite is an integrated part of the WordPress core. That means you won't have to download anything other than the official WordPress package to get set up. There are some basic system requirements that you should consider before even trying to install WordPress. At the most basic level, WordPress requires PHP 5.2.4 or greater and MySQL 5.0 or greater. You can see a detailed list of system requirements at http://wordpress.org/about/requirements/.

There are some basic things you should take into consideration before deciding to use WordPress multisite for your project. Most important is defining a project scope and making sure that WordPress provides enough features to meet that scope. It's possible that WordPress is overkill, in terms of features, for your project as well. It's all really dictated by the specific features your project needs.

Chances are, since you're reading this book, you want to set up a blog network of some type. WordPress multisite is used for a wide variety of reasons, from university class blogs to high-traffic websites or anything in between. The most common use of WordPress multisite I've seen is with small groups of individuals who want a blog but don't want to join a massive blog network such as WordPress.com.

WordPress didn't always include the multisite feature. Prior to WordPress 3.0, WordPress came in two flavors, regular and multiuser . WordPress 3.0 introduced WordPress multisite, as it's known today. WordPress 3.0 was released in June 17, 2010.