Since 1994, cookies have been used on Internet websites to (among other things) track the behavior of users. Web suffers who worried about privacy gradually found ways to get around cookies, or deleted them on a regular basis. Most people felt better.
Then came the Flash cookie.
Most Internet users are blissfully unaware of Flash cookies (also known as local shared objects. But half or more of all Internet sites now use them - for pretty much the same purposes that traditional cookies were used. The problem ...