When should you display a pop up?
You should display your popup slightly earlier than the average time visitors spend on specific pages. That means that you'll show them your popup after they've digested the information on your page, but just before they're thinking about leaving.
Should I use pop-ups?
Try presenting a pop-up based on some rules, such as:
Only show on pages that indicate they might have interest in a specific type of content offer. Show the pop-up after they've either scrolled down the home page, or after being on a page long enough to read some of the content.
Why we should ignore pop-ups?
In general, most pop-ups are a nuisance – they are usually advertisements and can even be malware, and most people would prefer not to see them. As a general rule, you should leave your browser's pop-up blocker turned on to avoid getting these pop-ups.