It can be hard to reproduce so I made a gif to demonstrate.

I'd like to see the conversion data related to this

It's pretty anoying actually, it does not detect when you are about to close, but when you put the mouse on the browser bar (on Firefox) so basically if you want to bookmark it or send it to read it later using something in the browser bar, you get the modal as well :/

Cute.

And lucrative (I imagine).

The conversion for that must be amazing. Hijacking someone's intended negative action with a surprise to draw you back into the sales funnel is very clever.

This is actually super simple. There's an open source library I work on that will do this for you: https://github.com/carlsednaoui/ouibounce

Sorcery!

Very clever. It almost worked on me, and I knew what it was doing.

http://www.picreel.com/

Powered by Picreel though I dunno how hard it would be to implement by its self.

This is bloody clever.