A fun way to secure entrance.
A mirror that is a voice and face biometric lock. Based on your voice, what you say, and your face (and expression) it will open the door.
Most subscribers never open your emails.
Insert the following (or similar) text at the end of your email’s short subject “Click here to get the gist of this quickly” and a link to the web page you are promoting in your email. When they click on the link directly from the subject line, they go to that page, but instead of seeing the page as a normal visitor sees it, they get an overlay window obscuring the underlying page, with a shorter version of the email (or the whole email if it’s short.) When they click on the CTA, they simply get to see the underlying page.
Try a new way to get an upsell and delight customers while doing it.
Use an animated opening of a new overlayed window that “opens” from the button itself with the upsell offer.