Too Long; Didn't Read
Ad blockers hide external ads, but they don't hide feeds, related content, and notifications of the site itself. These are built-in ads, put there by a site's own product designers, because they increase the time users spend on the site, which leads to more advertising revenue. Bad blockers need to work differently to ad blockers. They need to hide bads, but also need to let users show some bads when they want to. A database of bads will need to be created by analysing thousands of websites.