Hello!
I'm facing a dilemma.
I have to manage content of many websites (each of them has a lot of pages).
Currently, they aren't using DNN to manage content in fact (they are using another CMS, we are just trying DNN before deciding definitively use it or not). Sometimes, it's necessary to add and remove banners to the sidebars (publicizing events, things like that). Internal pages have the same look of the home page, so if a banner is added to the home page, it should appear on the internal pages too.

I am trying to figure out which is the best way to do it: by creating a page template or setting the module which should appear in all the pages as "display module on all the pages" (this seems to be not a good solution, since this cause the modules to be shown on the admin pages too). Actually, I use a HTML module to show the image of the banners, since they aren't comercial ads.

Is there some way so that I can effectively attend to this necessity of adding and removing banners/content to all the pages?

Thanks.

So isn't there a way to create a model page (like "Master Pages"), where every change in this page will be automatically applied to all the pages in my website?

To paraphrase Sebastian, you can create a set of skins, each one with their own banners and apply them to your pages. As time goes on this will not be easy to manage and you could end up with many different variations. Skin soup. This method would work best if A. All the banners are the same throughout the section and all pages in that section use the same skin and B. Your banners don't change very often

"Display on all Pages" modules would work, but you would have to visit every page and remove the banner modules you don't want. The admin pages aren't much of a big deal, remove them once and done.

Copy/reference an existing module, as Sebastian pointed out, would also be a solution. You copy a banner from another page.

You could do a hybrid approach of all three methods.

Those are the built in options at your disposal. Anything beyond that would be a custom module or skinobject. If you are handy with C#, you could write something in your skin akin to "If (the parent pageid = X){.//show something}"