By making it easier than ever for individuals to share their thoughts, social media has become a major conduit for information and a means of spreading ideas. But, for this same reason, it is rife with misinformation, insidious propaganda and unjust accusations. This lecture in applied Objectivist epistemology is about the questions we can ask ourselves before we post, share, comment, link or tweet, in order to make sure that what we are spreading is true and just.