I watched the entire hearing, it was pretty interesting. I was surprised how ignorant many of the senators were of the subject matter on hand. Some of them clearly didn't understand the difference between Facebook and the Internet. Or they thought that Facebook, Google, Twitter, were all the same thing, this mysterious "Internet" and somehow Zuckerberg was in charge of it all.
Some of the questions were impossible to answer because they made no sense and they kept hammering him for not answering it.
Then there were senators basically trying to guilt trip him into endorsing their bill when he already said he supports the principle behind it but it would depend on the details.