Pop, in cybersecurity and digital advertising, refers to 'pop-up' ads - online advertisements that suddenly appear in a new browser window or tab. These ads are often triggered automatically when visiting certain websites, especially those with questionable reputations. Pop-ups can be used for legitimate marketing, but are frequently associated with intrusive advertising, scams, or attempts to deliver malware. Users are advised to be cautious with pop-ups and use browser settings or security tools to block or limit them.