Not all of them use flash local storage objects maliciously, however. Many of them use local storage objects to actually track user preferences which is how they are intended to be used.

Is it supposed to be blank?

I would guess it's because I use "Click-To-Enable" for plugins in Chrome. Your battery, sanity and page responsiveness will thank you. (Not suggesting that CtE blocks this, just that much of it's probably an unnecessary result of Flash ads, etc on pages where you're not even using the Flash content)