From Nielson Norman Group: https://www.nngroup.com/articles/popups/
Summary: Whether modal or not, most overlays appear at the wrong time, interrupt users during critical tasks, use poor language, and contribute to user disorientation.
From conducting decades of user research, we know that people dislike popups and modals . I was reminded of this fact during a recent usability study. While attempting to complete a task, a participant tossed his phone across the table after encountering multiple popups, consecutively. Frustrated, he abandoned his task and left the website with a very bad impression of the organization. Several other users shared a similar sentiment, albeit they did not throw their phones.
A popup (also known as an overlay or popover ) is a window or dialog that appears on top of the page content. A popup can be classified according to two dimensions:
1. Whether the user can interact with the rest of the page: