System/words to be removed
It's time to remove system/words because it's no longer valid in R3.
In R2, the system/words object contained all words (system and user) and their global values. In R3, there is no such object.
In R3, the system/contexts holds words for different parts of the system. So, system/contexts/exports is the "library" available to your program, and system/contexts/user are the actual words used by your program. This approach let's you "overload" words in your program's context without affecting the system.
There may be a few developer tools that use system/words in R2, but I don't know if they are used in R3 as of yet. The conversion should be easy.
In addition, I should mention that the help function uses system/words, but we can change that to use system/contexts/exports. We should also talk about whether we want help to include user defined words -- a feature many of us have found useful. If so, we'll need to add that extra search.