For instance introductory section of Portal:Wiki is actually on a subpage Portal:Wiki/Intro and it is used in article itself, but also in the Main page, just as Project and Distribution portals intro pages.
Using subpages in the similar way are created other sections of any Portal page. Nice about this is that nothing prevents to use parts of portals anywhere we need them.
What if we can expand this concept to many more types of articles?
We gain ability to use parts of articles in any area; not only to link, but to reuse text. For instance, when we create list of used software to solve some problem then transclusion of intro pages in the list will tell reader, not only what is used, but also short introduction to software.
A bit expanded concept would keep current Template:Infobox on a subpage. That will make possible to list it in the right column of another article. Reader that has to install some software in order to perform task described in the article will have all information at hand that will assist him in installation.
Often used descriptions for procedures like "switch to root", or "switch runlevel" can be collected as subpages to one page for related actions and then just reused everywhere in the wiki. This will end tens of similar descriptions for those two all over the wiki.
How to make authors and copy editors aware of that?
It is relatively simple. Make them aware of option to use templates offered by MultiBoilerplate MediaWiki extension, and give them templates with example articles.
The openSUSE wiki version of MultiBoilerplate extension is improved by C. Boltz with ability to have different templates for different namespaces, so we have ability to be selective, depends on type of content that is offered.