Discount-driven popups are the most common because they work for transactional pages like product pages and pricing. The psychology is loss aversion: the visitor has to decide between leaving with nothing or staying for 10 to 20 percent off. The downside is that discounts train visitors to wait for popups, eroding margin over time.
Curiosity-gap popups work well for content pages and blogs. They open a loop the visitor needs to close, like 'The one mistake that costs SaaS founders 30 percent of their pipeline.' Visitors click because they need to know.
Value-first popups offer something useful (a guide, template, calculator) without asking for a discount or playing on fear. They work best for top-of-funnel visitors who are not ready to buy but are willing to share an email for real value.
Social proof popups use numbers or testimonials to validate the decision to engage. 'Join 12,000 marketers getting weekly growth tips' works better than generic 'Subscribe to our newsletter.'
Scarcity and urgency popups create loss aversion through time or quantity limits. They work best when the scarcity is real (genuine inventory limits, real expiration dates) and fall flat when it feels manufactured.