Pop-ups, e.g. are a type of advertisement that appear on websites or computer programs. They are usually small windows that appear in the foreground of the page or program and often contain advertisements or other content. The two crossword solutions for this term are ADS (3 letters) and FLIES (5 letters). ADS stands for 'ADS' and FLIES stands for 'Internet FLIES'. Both terms refer to the same type of pop-up advertisement.