- Login to your Google Apps admin
- Click on Manage This Domain
- Click Service Settings
- Click Documents (or Drive if you have Google Drive enabled on the domain)
- Check “Users can publish document to the public internet”
- Click Save
Note: If you are having issues with this not working, make sure that the when the document, ie a Powerpoint document is set to be shared with the public when adding it to your site article.
Note: It has also been reported by various sources that this was a bug and if you were running the free version you could activate a trial to the enterprise/paid version of Google Apps, check the box as above and then remove the trial. If you have the paid version, contact Google Support if you are having issues.