User:Sophivorus/sandbox

Global refers to things (modules, templates, gadgets, etc) that live in a single wiki, but can be used in every wiki, similar to how files live in a single wiki (Commons) but can be used in every wiki. Cross-wiki, on the other hand, refers to things that are copied exactly the same in several wikis.

Modules
Global modules do not exist yet and are not possible with current technology. Cross-wiki modules, however, are possible and do exist. They can be easily maintained using the Synchronizer tool, so that cross-wiki modules are almost as convenient as global modules would be.

Templates
Global templates and cross-wiki templates do not exist, and given the way cross-wiki modules work, neither makes much sense. If a template wants to become cross-wiki, usually the best approach is to become a cross-wiki module.

Gadgets
Global gadgets and cross-wiki gadgets both exist. Proveit is an example of a global gadget, while xxx is an example of a cross-wiki gadget.