Investors appeared relieved by Mr. Zuckerberg's Day 2 performance, with analysts like Ali Mogharabi of Morningstar welcoming the Facebook chief's apparent willingness to work on new rules. (He has a lot of homework .) But no one knows what they should look like. Lawmakers don't want to infringe first amendment rights or hold back innovation. And then is Facebook a tech company, as Mr. Zuckerberg says ? Or is it a utility or a publisher, to be watched by the F.C.C.? The biggest unanswered question, according to Kevin Roose of the NYT, is this: Does Congress have the political will to regulate tech companies? Elsewhere in Facebook news: Elon Musk thinks social media needs regulations. Brian Chen's reaction to what data Facebook had collected about him: " Yikes ." How the company targets you for advertising. Craig Newman argues in Another View that companies should be graded on their data security. And Cambridge Analytica's interim C.E.O. is stepping down.