Zuckerberg’s Time in Washington Well-Enough Spent 

Facebook CEO survives grilling as fractious lawmakers seem unlikely to take harsh action

Everyone seems to be angry at Facebook FB -0.99% these days, though for wildly different reasons. That, in turn, may work out just fine for the social network—and its investors.

Such was apparent after Mark Zuckerberg spent two days under sometimes tough questioning before Congress this week. The Facebook CEO made his apology pilgrimagefollowing a scandal involving Cambridge Analytica’s use of Facebook user data in the 2016 U.S. election and other campaigns across the globe.

This has proven to be the most serious scandal Facebook has faced, raising the risk of users fleeing and governments intervening. Up to last week, the company had shed nearly $80 billion in market value since the Cambridge news broke in mid-March. In that light, Mr. Zuckerberg’s main job this week was to calm both lawmakers and his own investors. He appeared to succeed at the latter; Facebook’s stock price rose more than 5% over the two days he was in Washington.

As for the former, while there is no shortage of pique directed at the social network, Congress seems hardly of one mind about what actions—if any—to actually take. The questions ranged widely, but most lawmakers seemed more interested in grandstanding than eliciting constructive answers from one of the world’s youngest multibillionaires. This allowed Mr. Zuckerberg to largely stick to his talking points, and made the possibility of onerous regulations that could upend the company’s advertising-driven business model seem somewhat less likely.

But investors shouldn’t be too sanguine. New privacy regulations take effect in Europe next month, and efforts to reform privacy laws are also under way in the U.S. These could impact the social network’s usage and, thus, the growth of its advertising business. The scandal also has made clear Facebook’s need to keep tighter control over activity on its platform, which will raise its costs and thus crimp its legendary bottom line.

As for Mr. Zuckerberg, he needs to lead the company through those coming changes with a more deft hand than he has shown to date. And that will make his two days in Washington look easy by comparison.