It's amazing how Mobirise keeps on coming up with things I added to QS years ago. Check out https://mobirise.com/extensions/popup-builder/

Their next big thing would obviously be a way to provide content behind passwords. This can be done with just JavaScript. Mobirise *could* encrypt html that can only be decrypted with a given password. This library seems to do the trick. This solution comes nowhere near the QuickerSite intranet area, but in many cases that is not needed.