A pop-up form is a sign-up form that appears over the page a visitor is reading. It can be triggered after a delay, when the visitor scrolls a certain distance, when the mouse moves towards closing the tab (exit intent), or when they click a button. Variations include slide-ins from the corner, sticky bars along the top or bottom, and full-screen overlays.
Pop-ups work because they put the sign-up offer directly in front of a visitor at a moment when they are engaged, instead of leaving it in a footer few people see. For many websites they bring in more subscribers than all other forms combined, especially when paired with a clear reason to sign up, such as a first-order discount or a useful guide.
They also irritate people when done badly. A pop-up that appears the moment the page loads, covers the whole screen on a phone, has a tiny close button or reappears on every page will cost you visitors. Wait until someone has shown interest, limit how often a visitor sees it, hide it from people who are already subscribers, and make closing it easy. Google may also treat intrusive mobile pop-ups that block content as a poor experience.
Match the pop-up to the page. A visitor reading a blog post on choosing a laptop is a good candidate for a buying guide; a visitor on the checkout page should not be interrupted. Using different pop-ups for different sections usually works better than one generic offer everywhere.
A Pune home-décor store shows a slide-in after visitors scroll halfway down a product page, offering ₹200 off the first order for subscribing. It appears at most once a week per visitor, never on the cart or checkout pages, and not at all for existing subscribers.
MailNesto pop-ups can open after a delay, on exit intent, at a scroll depth or on a click, limit how often a visitor sees them, target pages and devices, and stay hidden for people who have already subscribed.