As soon as you start typing in a field where a list is defined, suggestions from the list will appear. If the word is not in the list before, it will be in a different color from the other text as a sign that the word is new to the list. Press Enter to select a term from a list.
You can also get an overview of the contents of the list by pressing «Ctrl + 1» (This is equivalent to the command Open term lists.)
This feature is useful for keeping track of e.g. a consistent use of author names, keywords, etc.
Should you need to change something already posted, there is a useful feature in the form of Change text.