CONS: Its users are mostly from the English-speaking developed world, at least for now, and appear to be mostly left-wing. Also, those early-Twitter vibes might not be what you're after. One tech journalist said it has "theater kid energy"; another called it "millennial roommate board game night energy". Oh, and you still get glitches and outages sometimes.
WHO'S THERE? News junkies and political anoraks; academics, policy researchers, authors, and journalists (so many journalists). In other words, nerds.
A fellow Twitter junkie once told me that Instagram is for hot people, whereas Twitter is for ugly people who had no choice but to learn to be funny. If that's true, who is Threads - a Twitter clone by Instagram - for?
At present the answer seems to be: lifestyle influencers. Celebrities. Casual users. Normies and turbonormies. Liberals engaging in election denial conspiracy theories. A smattering of journalists and politics-heads complaining about the algorithm. Posts are definitely just called posts, thank God.
To be clear, Threads is vastly more popular than Bluesky, with roughly 275m monthly active users as of August compared to Bluesky's 17m or so today. In fact, the number of users Threads gained this month so far is nearly equal to Bluesky's entire audience.
But for me it also feels more staid and locked down, with the same heavy-handed AI-powered moderation that has become a trademark Instagram's parent company Meta (which also owns Facebook) and a doggedly algorithmic default feed that blurs together posts from five seconds ago and two days ago and frequently shows you posts you've already seen.
PROS: Chiller and more laid-back than Bluesky, with a far bigger audience. Strict anti-nudity rules, if you're into that sort of thing. Integrates with Instagram. Also deliberately de-emphasises politics, so if you want to steer clear of political discussion it's a great place to be.
CONS: As I mentioned, Threads does not like politics, or news media in general. Instagram CEO Alex Mosseri has said most users aren't interested in that, and while he initially claimed that the app wouldn't "discourage or down-rank news or politics", it later reversed course. It's also difficult to find new people to follow and near impossible to escape the grasp of Meta's recommendation and timeline sorting algorithms. Obviously, using Threads also lines the pockets of Meta and Mark Zuckerberg, which you may have Opinions about. Also, still glitchy sometimes.
WHO'S THERE? Everyone not on Bluesky and Mastodon, apparently.
Mastodon is the most complicated contender. Like Bluesky, it is designed to be decentralized, and not controlled by any one person or organization. But whereas for Bluesky this mostly happens behind the scenes - and much of it is still in the future - with Mastodon it's front and center.
Rather than one monolithic social network, Mastodon is really a federation of different social networks that all talk to each other. When you create an account, you must choose a specific "instance" to be your home. Instances can be run by anyone: companies, universities, private companies, or just enthusiasts, and each one has its own rules and moderation procedures. If this sounds like a high-pressure choice, by default you can just pick Mastodon.social - run by a non-profit founded by Mastodon's creator Eugen Rothko.
Once you're in, it's not too confusing. Posts - called 'toots', I guess - can be up to 500 words, giving it a bit of a Tumblr-y, bloggy feel. Unsurprisingly for such a (relatively) complex service, the user base seems to skew heavily techy.
Mastodon is part of what's called the "fediverse", a loose connection of social media sites that use the same underlying technical standards. The hope is that, at some future point, all these services will work together; that choosing a social network will be less like picking between Netflix and Disney+ and more like choosing a web browser or an email service. Each service's content would be visible through all the others, and users would simply be deciding how they want to engage with the underlying activity.
Even now, Threads is actually partly compatible with Mastodon, allowing you to automatically make your Threads posts visible on fediverse services. So perhaps one day the real Twitter successor will be all of these services simultaneously. Or perhaps not.
PROS: Decentralised, with a high degree of user control; hell, you can even set up your own instance just for you. Or just find an instance whose operators you like and trust. You're a free speech absolutist? Someone's probably catering for that. Want zero tolerance for fake news or bigotry? Likewise. It's also extremely customizeable, with very granular privacy settings.
CONS: Steeper learning curve than other services. Hard to find people to follow, now that most automated follow import services have been broken by Elon Musk's policies.