It provided witnesses who have been unwilling or unable to give full answers to the Committee's questions. This is the reason why the Committee has continued to press for Mark Zuckerberg to appear as a witness as, by his own admission, he is the person who decides what happens at Facebook. … Tech companies are not passive platforms on which users input content; they reward what is most engaging, because engagement is part of their business model and their growth strategy. They have profited greatly by using this model.