I understand the use of 3rd level (sub domains) but I am unclear if they are necessary to operate the Mobile Joomla or if the 'Out Of The Box' configuration will provide functionality as well. I don't see specific reference.

Thus, what this leads me to believe is that a totally different web site needs to be built to provide true mobile functionality and viewing. Anyone with input in this regard?

Hi,
I'll try to answer the question. The short answer is no, yes and no.
Let us assume, for the sake of argument, that there are two types of browser: Mobile and desktop.

When a visitor views a website using a browser, the website formats the output using a template.
The visitor sees a combination of:

website material -> template -> browser (either on the mobile or desktop) -> eye of the beholder.

Some websites have a special address which is just for mobile browsers.
e.g Google uses for desktop and if you visit with an iphone it automagically changes it to The Guardian newspaper, (other search engines and newspapers are available) uses and in other words there is a convention that if you want to view the mobile version of the website, you must visit the correct address, or be redirected to the correct address.

Mobile Joomla (MJ) allows you to set this up BUT it does not need it. Out of the box MJ will intercept the process. It does this by examining the User agent string of the browser viewing the website.

Each type of browser has an identfying character string that describes the capabilities of the device using it. (This may or may not be true because devices can pretend to be other devices. This is one way of testing a website to ensure it works with various browsers).

Anyway MJ makes a quick check to see if the browser/device is one of the common ones, if not it uses the tera-wurfl database to identify the browser. If the visitor is using a desktop, then MJ leaves well alone and the process continues as above.

If the visitor is using a mobile, then MJ determines which protocol is best for that device. There are 4; iPhone, XHTML (which is blackberrys and other smart phones), chtml (1st generation smart phones and pdas), wap (really old phones that use the original wireless application protocol). (MJ allows you to tailor this process to include/exclude unsupported tags, gzip and so on. This is so you can match the content of the website to the devices used to visit it.)

MJ then uses one of the templates better suited to a mobile device rather than the default site template. You can choose which template it uses for each of the 4 protocols, but be aware that only the XHTML and iPhone templates are suitable for those types of devices. In other words you can't use an iphone template on a wap phone.

By this means, a visitor using a mobile, gets a view of the site tailored (that is the pictures are smaller*, and the layout fits the screen) for the device. This happens without visiting a "special" (m.mysite.com) version of the site.

A lot of confusion comes because MJ contains parameters that allow you to specify a "special" iphone.mysite.com or m.mysite.com and it is possible to have an oscillating process which may cause too many redirects. Add to this it is possible to use a .htaccess file outside of Joomla and MJ to do redirects and there is scope for much hairpulling.

But the short answer is that out of the box MJ should make a site work (ie be legible) on a device other than a desktop. There may be extra work to do to make it work with other plugins and modules which are also intercepting and working with content.

Hope that helps.

PS I made an assumption, mobile and desktop; MJ allows for some types of tablet to be recognised and handled separately. The "screen size" of mobile devices is definitely not one size fits all.

*The resizing of pictures only happens if the picture is from the site. In other words if the picture is referenced on another website, MJ will not resize it.