Kissmetrics uses a "disguised" pop-up: unobtrusive and designed to look like an email, this pop-up offers to sign up for their newsletter once you've scrolled almost all the way down the page.
Kissmetrics
Alternatively, you can create a window containing a link to bolivia phone number data recommended and relevant content. Business2Community added such a pop-up to its resource:
Business2Community
Split Test: Will a Personalized Pop-Up Increase Product Landing Page Conversion?
Windows that pop up at a specified time
These aren't just pop-ups that appear when you're about to leave the page - they give you time to relax, lull you into a false sense of security, and then BAM!

When it comes to timed popups, timing is key. Marketers at AppSumo recently published a study that found that the best time to show a pop-up is exactly five seconds. Yes, even one second matters. The graph below shows the conversion rate as a function of how many seconds the pop-up appeared:
AppSumo
4 Alternatives to Traditional Pop-Ups
Pop-up windows with a question
Some pop-ups contain a question that most people will answer yes to. The funny thing is that they leave little choice. When you work on creating such a window, make sure that you do not use phrases to close it that are humiliating or embarrassing to your target audience: