edit to add... this is like some sort of Russian roulette. ignoring the Russian connection pun, that's still a funny joke.

It seems to me that zuckerburg cares about ad revenue, which means he needs eyeballs and needs to keep them for as long as possible. And, he has proven to care very little about privacy. Therefore, for those who can't shake the habit 100%, cutting back to one day a week is a good way to get the connections you need while slicing into the attention getting ad revenue.