In particular, notifications function in those browsers, which was invented and developed for convenience on news and video sites, is exploited by third-party advertising cloacas, like Captcha-verification.systems and similar, for delivering unwanted and fairly annoying ads directly to the desktop. Captcha-verification.systems is an untrustworthy and even dangerous website, that uses technical features of modern browsers (Google Chrome, Mozilla Firefox, Edge, Safari) to push ads, pop-ups, and notifications to users desktops.