1) The credit card industry's term of art for false positives in fraud detection is "insult rate". If you've ever swiped your card at a shop and had it declined, you understand why.
2) A large auto insurance company has discovered that if a household owns two identical cars (same make, same model), that household's driving risk is very low. They have termed this "the boring factor".
3) Cable companies have trouble figuring out whether you are actually watching TV - the box might be on, but the TV is off. But by inspecting remote control button presses and using predictive models, they can figure it out. If you hit the volume button, for instance, you're almost certainly watching. And yes, that means every button press is probably being logged.
4) Look for paginated articles on news websites to start disappearing. Paginating articles is a way for content providers to "manufacture capacity" (ie. create pageviews against which they can sell advertising). But new display advertising technologies only register an ad impression when the ad is actually viewed (so ads at the bottom of the page aren't counted if the user never scrolls them into view). With the incentive for pagination gone, look for more long, scrolling articles.