Mark Zuckerberg: "The most concerning of these to me is time spent... Of course the other goals are all important as well, but this is the one that threatens our core narrative the most."

"The most concerning of these to me is time spent. Most of these goals I view as in our control, but time spent seems more subject to macro trends we're just trying to predict around the balance of apps people will use and Facebook's place among them. If we think we're doing the right things to drive time spent and the number still isn't increasing much, that suggests our thesis on how we expect people broadly to spend time and use different apps could be wrong. That might imply our core product growth is flat or close to falling into decline, which would mean we'd need to very rapidly shift emphasis to other areas to accelerate future growth, like in messaging. It's too early to conclude how this will look at the end of Q2, especially with all the measurement issues. But if we end up meaningfully below our goal here, we'll need to have some tough conversations about where we focus to make sure we're spending our time building the products people will increasingly want in the future. Of course the other goals are all important as well, but this is the one that threatens our core narrative the most."