> Mr. Zuckerberg, what year and month did you personally first become aware of Cambridge Analytica?”
Unless I missed that the hearing was highly related to this, why would he remember this exact date offhand?
You'd be better declining to answer this question than guess and get it wrong which seems like what he did. Asking if he became aware of them before or after a specific event would have been much more reasonable. There's tons of important events in my life where I don't know the month it happened because it's not important to remember.
I think he's right to say "I don't know" when he can't be completely sure. That's not a zinger.
Likewise, it's not a zinger when you ask a really long question that contains several factual claims that you require clarification on, or try to force a yes/no answer to a loaded question (see https://en.wikipedia.org/wiki/Complex_question#Complex_quest...).