Time-based media is distributed and promoted in a social networking environment. Accounts of a social networking system author social media content items (SMCIs) from which a social networking system infers relevance of content to users of those accounts. Content distributors submit time-based media content to the social networking system, which creates distributor SMCIs containing the time-based media content. Accounts are identified to receive distributor SMCIs based on SMCIs previously authored by those accounts as well as identifying information and the subject of the SMCI. Content promoters may add promotional material to distributor SMCIs, which the social networking service sends to additional accounts.