What is WordPress MS?

WordPress MS (or Multisite), also called a "Network", allows you to create a network of WordPress sites.  Instead of only a WordPress site on yourdomain.com, you can create more WordPress sites as subdomains.  This allows you to manage all the WordPress sites from one Admin page.  For example, you can have independent WordPress sites on site1.yourdomain.com or site2.yourdomain.com, almost like mini blogs.

Should I use WordPress or WordPress MS?

Not all websites require running a WordPress MS.  If you plan on having one WordPress website per domain, WordPress MS wouldn't be required.  However if you plan on creating a network of WordPress websites, than you may consider WordPress Multisite.  Some of the main advantages are:

• All upgrades, plugins installed, and themes downloaded will effect all sites in the Network
• Allows you to have multiple WordPress websites based off of one domain
• Easily offer blogs to your visitors as subdomains of your website
• Manage a client's WordPress site through your Dashboard

Can I install WordPress MS?

Yes, you can install WordPress MS on your account.  It can take time to get it working properly though and is not a one step process.  However, once the network is set up it's easy to add more sites to it.  Click here for a guide on installing a WordPress Multisite.