Bluesky vs Mastodon vs Threads: which should you post on?

Bluesky, Mastodon and Threads look similar and behave nothing alike. What each network is actually good at, and who should pick which one.

These three get grouped together because they are all text-first and all arrived in the same window. Underneath they are three genuinely different bets about how a social network should work, and the differences show up in your day-to-day posting rather than in the technical detail.

I build a scheduling tool that publishes to all three, so I have no reason to prefer one. What follows is the honest read.

The short version

• Bluesky — chronological by default, algorithmic if you choose. Best if you want reach without an algorithm deciding for you.
• Mastodon — chronological, community-moderated, no algorithm at all. Best if you want conversation over reach.
• Threads — algorithmic, enormous, tied to Instagram. Best if you already have an Instagram audience.

How posts actually reach people

This is the difference that matters most and the one least often explained.

Threads ranks. An algorithm decides who sees what, which means a good post can find an audience far beyond your followers — and a post at a bad moment can be resurfaced later rather than lost. Volume and consistency are rewarded.

Mastodon does not rank at all. Your followers see your posts in order, and that is the whole mechanism. Nothing goes viral by algorithm; things travel by people boosting them. Reach is smaller and more deliberate.

Bluesky does both, and lets you choose. The default Following feed is chronological, but custom feeds are a first-class feature and anyone can build one. That makes discovery possible without making it compulsory.

"On Threads you are writing for an algorithm. On Mastodon you are writing for the people who chose to follow you. Bluesky lets you decide which."

Culture, which matters more than features

Mastodon is the most opinionated. Content warnings are used liberally and expected. Self-promotion lands badly. Alt text on images is close to a social requirement rather than an accessibility nicety. If you arrive posting like a marketer, you will have a bad time, and that is by design.

Bluesky feels closer to early Twitter — faster, funnier, more tolerant of self-promotion, with a strong technical and creative population. Custom feeds mean niche communities form quickly.

Threads is the most mainstream and the most brand-friendly, with the least tolerance for anything that reads as argumentative. Reach is real; conversation is thinner.

Practical constraints

• Post length — Bluesky 300 characters, Mastodon 500 by default (servers vary), Threads 500.
• Scheduling — Bluesky has none built in. Mastodon has it in the API but not in the official apps. Threads supports scheduling through its API.
• Editing — Mastodon lets you edit. Bluesky does not.
• Content warnings — Mastodon only.
• Portability — Mastodon migration moves followers, not posts. Bluesky's protocol makes stronger portability guarantees. Threads is Meta's.

Do they connect?

Mastodon and Threads both speak ActivityPub, so a Threads account that has opted in can be followed from Mastodon, with replies flowing back. It is partial: fediverse content sits outside the main ranked feed by design.

Bluesky is on a different protocol and cannot talk to either directly — though a bridge exists if you want Bluesky and Mastodon connected.

So which one

Pick Threads if you have an Instagram following. Bringing it across is the single biggest advantage available on any of these networks, and nothing else compensates for starting from zero.

Pick Bluesky if you want to build something new and want reach to be possible without being algorithmic. It is the best of the three for finding an audience from a standing start.

Pick Mastodon if you want conversation with people who chose you, and are genuinely uninterested in scale. It rewards a completely different behaviour from the other two, and people who go in expecting reach tend to leave disappointed — more so if you are posting as an organisation.

Pick more than one only if you can write for each. Syndicating identical posts to three networks is visible from a distance and works on none of them. If you do run several, the cross-posting options are here.