What is Work Item Promotion ?
Accepted answer
First of all, this feature is an "Enterprise Extension", which means it is only for mainframes like the IBM Z series machine.
On mainframes, for various reasons, it is common practice to "promote" derived files (files like object code and binaries built by a build tool), rather than just rebuild them (which is what is done in most/all builds for non-mainframe systems).
What work item promotion does is let you "promote" the derived files that are associated with the change sets that are linked to a given work item.
If you are a mainframe user, this will probably be obvious, and if you are not, you probably have no idea what this is talking about (:-).