If you're subscribed to the Plus Plan, the Re:amaze FAQ includes an Article Edit History feature, which allows you to see:
Previous changes to each article
When an article was last updated
Which staff members have made edits to an article
In the Article editor, you'll be able to access the Article Edit History by clicking the "See Edit History" button.
NOTE: The "See Edit History" button will only appear for articles that have had previous edits.
The Article Edit History will include all past versions of each article, as well as display content that has since been added and removed.