Why most popups fail
They fire on a timer or on exit intent, for every visitor, with a discount or a newsletter. They don't know who's reading pricing for the third time and who landed by accident.
What a good one does
It waits until there's a reason to speak. It asks one question with tap-able answers, not an email field. And it changes what it offers based on the answer.
It also takes no for an answer: no repeat questions, and a pause after someone says no thanks.
Examples
A plumber: “How urgent is it?” → urgent visitors get the phone number and WhatsApp; planners get a call back. An agency: “What are you planning?” → a call with the right person. A shop: “What's holding you back?” → a size guide or a WhatsApp chat.
How Signal's popup works
Signal's popup is small, sits in the corner, and only appears when its estimate of what the visitor wants is unsure and the answer matters. You write the questions and offers (or the wizard suggests them), and it never asks the same thing twice.