INSTAGRAM SAYS CAPTIONS MATTER. THE REAL SHIFT IS CONTEXT

Summary from the TLDR Marketing newsletter

The caption is no longer supporting copy on Instagram: it is becoming the context layer that tells people and search engines what a post actually means. The same photo could be a new release, an archival find, or a personal memory, and the caption is what tells the difference once content travels beyond a creator's own followers. Public posts from professional accounts can now be indexed by external search engines, so captions increasingly shape how content gets found.