Mastodon Caption Optimizer

How discovery actually works here

There is no recommendation feed. Your post reaches your followers, and it reaches anyone else only if someone boosts it or if they are following one of your hashtags. That inverts the usual advice: hashtags are not decoration on Mastodon, they are the discovery mechanism.

Most instances do not offer full-text search over other people's posts by default. If a topic word is not in a hashtag, it is effectively unsearchable. Two or three well-chosen tags — capitalised for readability, like #ClimateScience — do real work.

Boosts are the amplification. There is no quote-boost culture pushing dunk engagement, so posts that are genuinely useful or interesting get passed along, and posts engineered for outrage mostly do not.

Length, content warnings, and etiquette

500 characters is the default limit, though some instances allow more. Write to 500 — your post federates to instances that enforce it, and a post that gets truncated elsewhere reads as broken.

Content warnings are used far more liberally than newcomers expect: politics, food, health, spoilers, long threads, and anything heavy. Using them correctly is the clearest signal that you understand the culture, and misusing them is the clearest signal that you do not.

Alt text on images is close to mandatory. Posts without it get called out, and many accounts will not boost an image post that lacks it.

Automated cross-posting from X with its hashtag habits and truncated links intact is the single most disliked pattern on the network. If you cross-post, rewrite.

Common Mastodon mistakes

Treating it as a broadcast channel. The fediverse is conversational and small-scale; accounts that only publish and never reply get very little traction.

Zero hashtags. On other platforms that is defensible; here it means nobody outside your followers will ever see the post.

Marketing register. "We're thrilled to announce" is fine on LinkedIn and reads as an intrusion here.

Ignoring instance rules. Each server has its own policy, and moderation is direct and fast — an admin will simply defederate or suspend, and there is no appeals queue to escalate to.

Posting into the void at the wrong hour. With no algorithmic resurfacing, a post that lands while your followers' instances are asleep is gone; timing matters more here than on any feed that re-ranks.