It is recommended to use pop-ups only for very specific purposes, such as a registration form. However, it should be ensured that pop-ups are not too obtrusive and do not include very striking advertising messages. Pop-ups are recommendable for help functions, by displaying useful information. However, important information should not be included in such, because many users use a pop-up blocker for their own security and better usability of the Internet.
The pop-under is a special form of pop-ups. Both have in common that they open in a new window with an advertising message when a certain action is performed. Contrary to pop-ups, a pop-under does not open in front of the website, but in the background. The window is indeed open, but will only become visible once you close or minimize your browser. Pop-under banners have the purpose of greater consumer acceptance of advertising. While the pop-up often annoys because you get disturbed in your current projects, you won’t see the pop-under until you have reached your goal and closed the browser. The problem with simple pop-unders, however, is that they can be blocked similar to popups with pop-up blockers.
Whether the use of pop-ups adversely affects the ranking of a page is not known. However, there is some evidence why you should dispense with pop-ups on your website:
It is recommended to use the pop-ups only in a well-thought-through context, for example, for a registration form. However, it should be ensured that the pop-ups are not too obtrusive and do not include very striking advertising messages. It makes sense to use pop-ups for help functions, where useful information will be displayed to users.