Pay attention to the new features that were added yesterday afternoon: http://hub.arcgis.com/pages/changelog
A few of us at ISD learned the hard way and it was very frustrating trying to tell what was going on since we were not notified of the new features. When editing your Hub site or page, there is now the ability to preview draft, publish draft, view published, and delete draft right under the ‘Save’ drop-down menu. If you’ve made changes to your site or page, clicked Save, and are happy with your content language and style, make sure you publish your draft.
Otherwise, your site and page remains unpublished and you won’t see your changes go through. You’ll also see this tag ‘Unpublished draft’ on top of your site:
These new functionalities are similar to what you may have experienced when publishing a post to WordPress or have used StoryMaps.