Social Media Marketing: Foundations to Practice · How Social Media Algorithms Actually Work
From Chronological Feeds to Interest Graphs
Nearly every major platform has abandoned chronological feeds in favor of algorithmic, interest-based ranking. This chapter covers what that shift actually means for a brand's content.
As of 2026, essentially every modern platform ranks and displays content algorithmically by default, with Bluesky standing out as a notable exception where chronological display remains the default, though platforms like X, Facebook, and Instagram still offer chronological as an optional, non-default view [10]. This shift, which unfolded gradually over roughly a decade, fundamentally changed what determines whether content is seen: publishing to an audience is no longer sufficient, since the algorithm decides whether and how widely that content is actually distributed.
- Nearly every major platform now ranks content algorithmically by default; Bluesky is a notable chronological-default exception.
- Platforms have shifted from follow-graph to interest-graph models, meaning followers no longer guarantee reach the way they once did.
- Feed algorithms score a large candidate pool of posts for predicted engagement, ranking them within milliseconds of a user opening the app.
- Marketers must now optimize for the specific signals an algorithm rewards, since follower count is an increasingly unreliable proxy for reach.