The Senate Commerce Committee is holding a hearing to review Section 230 of the Communications Decency Act, which protects tech companies from liability for the content people post on their platforms. Jack Dorsey, CEO of Twitter; Sundar Pichai, CEO of Alphabet Inc. and Google; and Mark Zuckerberg, CEO of Facebook, are expected to testify. The hearing will focus on consumer privacy, content moderation, and transparency and accountability among big tech companies.