How do social media algorithms actually work and what signals matter most?

Algorithms sort content to show users what they'll find interesting based on their history. Key signals include: your interaction history with the author, how popular the post is, watch rate (25-50% is good, over 50% is excellent), and whether viewers engage through comments, shares, and messages. For reaching current followers, interaction and consistency matter most. For gaining new followers, popularity is the primary signal. You need both parts of 'social media' - being social (responding to comments, engaging with others' content) AND posting media consistently.