Content for Desktop/Tablet
This should only display on a desktop or a tablet with medium resolution - why the width is as it is.
Googlebot may ignore this content completely as the default googlebot is googlebot smartphone.
This page is an experimental page and should not be indexed as it has a Meta NOINDEX and does not have an entry in a sitemap.
Another experiment where I do want Google to index the page will contain content that will only be in the mobile section the dektop section will only have content that explains that the page is an experiment.
The other advantage of a "desktop only" section is that I can have links to pages that I have removed from the Google index and had removed from the server. These pages have had a NOINDEX added to them and the only way they can be accessed is via a direct link from a page such as this.
The problem was that I was posting information that was deamed to be disparaging and a "diatribe". My intention is that the content cannot be found making a search and the only way it can be accesed is via prior knowledge of its existance. Not that this will be understood by those that have taken offence!
Content for Mobile
This should only display on a Mobile
If the text on the top bar results in a wrap then need more headspace.
This content will be indexed by Googlebot - other search engines may handle the content differently.
Regardless of how the page is indexed this technique will be useful when I know that the target audience is likely to be using their "fat fingers" to make endless searches on their mobile phone. I can then restrict my "diatribes" to either the mobile pages or the dektop ones, depending on what I am trying to achieve.
Content on "Common Content" sections will be indexed regardless. This paragraph is in the "common" section.
About the Common Content
Some pages may require common content. This text should appear on all resolutions.