So why are pop-ups so very bad? Pop-ups create bad user experience and generate high bounce rates. A bounce rate is the percentage of users who enter a site and then exit without navigating to other pages, or people who quickly push the back button because they immediately see something they don’t like, or are delivered irrelevant content that is not what they were searching for.
Users have a very strong distaste for pop-ups and will tend to associate that distaste with the websites that employ them. So if you want someone to not only leave your page immediately, but also associate your website/company with a bad experience, then by all means, use pop-ups. But if you want people to navigate around your site and leave with a positive experience, then serve them relevant ads that deliver them to a relevant landing page.
Give users what they want and they are much more likely to return the favor.