Pop-up advertisements are a form of internet advertisements that appear in a separate window, either as a full screen (but behind the current window, and also known as a Pop-under ad.) or partial screen (over laying the current window). These advertisements, similar to some interstitial advertisements, do require the user to take some form of action (even if it is to simply close the window). The benefits are the user can simply continue to browse the web without being interrupted, yet still engage an action with the advertisement if desired, at a later time (unlike other forms of web advertising). Balancing this, they do create another window in the user's screen, that the user did not request, this can be considered somewhat annoying.