Browser Notification Spam (BNS) is a type of online spamming technique that exploits the browser notification feature. This feature, introduced by web browsers like Chrome in 2015, allows websites to send notifications to users who have subscribed to them. However, BNS occurs when unscrupulous advertisers misuse this feature for click fraud. They trick users into allowing notifications from websites that are designed to generate clicks for ad revenue. Once users allow these notifications, they are led to the browser notification spam sites through various doorway pages. These pages are designed to attract user visits and redirect them to the BNS sites. Spammers use fear or misleading notifications to convince users to allow notifications. The result is users receiving unsolicited pop-up advertisements while browsing the internet, which can be misleading and disruptive.