Besides covering basic differentiations, this article could serve to improve the quality of the Wiki by avoiding repetition. How many articles say: "edit in ~/.bashrc, or zhrc (if you're using zsh) -- alternatively, edit /etc/profile.bash for system-wide changes" or something to that effect? And even though it sounds counterintuitive, expanding this article makes the Wiki better for advanced users as well, since they won't be presented with the same old information they're accustomed to skip.
We could have a basic run down of common file locations and what they mean, instead of explaining them in every article. Editors can just say "add the following to the shell's configuration" and readers would then decide whether they want it system-wide or not, etc.
Just like article:ABS is referred to in every page that involves compiling, this page could serve the same kind of utility.