When you are selecting your keywords in your broadcast you may think to yourself where did all of my keywords go that I have in the system?

The reason you won't see all your keywords is because the keywords for Broadcasts are specifically limited to your lists and the contacts that are attached to that those keywords. 

When selecting keywords you are really choosing different lists to send your broadcast out to and you can leave this blank to send it to your whole list or you can select different keywords for different lists.