What Is The Difference Between www, www2, www3 etc?
In most cases there is no reason for you to even use the www before the domain name that you are typing into the address bar in internet explorer, firefox, netscape, or Safari (Safari is now available for WINDOWS! - see my post on that)
The bare bones portion of any domain name is simply the part before the .com - for example: YourDesignServices.com
The period that comes before the domain indicates a sub domain - for example: subdomain.domain.com
Since the birth of public internet access using internet explorer WWW had become the common sub domain for the website portion of the domain name.
Subdomains serve the purpose of pointing users to different servers attached to the domain name - for example:
http://www.YourDesignServices.com - points to our webserver
http://client.YourDesignServices.com - points to our clients development server
http://mail.YourDesignServices.com - points to our mail server
http://store.YourDesignServices.com - points to our online ordering (ecommerce) server
So in an organization that has differnet servers, maybe in different locations, running different portions of the website, for simplicities sake, you may be redirected to www2 or www3 and so on for the different portion of the website you are using.
So there you have it, www, www2, www3 are all the same, they are just different subdomains within the same domain name.