Lawyers’ professional use of social media is widespread and a critical component to running a successful practice. Yet some common uses of social media easily — and often innocently — violate the professional rules of ethics. The American Bar Association recently passed amendments to the Model Rules of Professional Conduct to include topics related to social media use, but the amendments still do not address all issues. Likewise, advisory opinions of state and local bar associations and court opinions give scant and sometimes contradictory advice about when a use does or does not violate a Rule. This essay discusses four topics at the intersection between social media and ethics, chosen because they are either unsettled, very common, implicate Rules that are easy to violate, or all three. The topics include when posting turns into advertising; when posting breaches confidentiality obligations; using social media to investigate during discovery; and using social media in court, including investigating jurors and friending a judge. This essay presents the issues involved under each topic, the state of play in various jurisdictions, and solid recommendations for practitioners to take in order to remain confident as well as ethical users of social media.