But wait, I don’t get it. Why do they work?
The long and short of it is simple: pop-ups require a visitor to
take action, either positive or negative.
Let me repeat that. Pop-ups require a reader or visitor to your
landing page to, actively, say “No” to your offer.
And when you put something awesome in front of someone
and require them to consider it as a possibility, the
chance of them converting on it is far, far higher than
it is if they have the option to simply leave.
Pop-ups are like milk: un-bounceable.