They don't. The biggest thing people on HN tend not to realize is that they aren't the target market for this kind of stuff. Alerts drive engagement, otherwise devs wouldn't waste the time to put them in. Same with ads and analytics stuff, they are a nightmare to put in and maintain but it's the surest way to make money.
I hope eventually the metrics emphasis shifts from quantity of interaction to quality. Take a lesson from my hammer, which doesn't scream out from my toolbox every five minutes saying "tap me!".
