Bluesky, the Jack Dorsey-backed decentralized social network, isn’t publicly available yet but it’s already become one of the buzziest Twitter alternatives. Scoring an invite to the service, which has been in a closed beta for barely two months, has become a sought-after status symbol with invite codes selling for hundreds of dollars on eBay.

The iOS app has been downloaded more than 375,000 times, according to analytics from data.ai, and the app has already become one of the most popular social media apps in the Play Store barely two weeks after launching. Those numbers may not seem particularly impressive, but considering the app only has about 65,000 users, it’s clear that demand for the service is far outstripping the number of available invites.

What is Bluesky?

Bluesky started in 2019 as an internal project at Twitter with the goal of creating an open source decentralized standard for social media. Dorsey, a longtime proponent of decentralized networks, had long championed the idea of such a standard, saying he hoped Twitter could one day “be a client of this standard.”

Bluesky went independent in 2021, and officially ended its association with Twitter in 2022 following Musk’s takeover of the company. Bluesky is now overseen by CEO Jay Graber, along with a small team of developers. Dorsey is still attached to the project — he has a seat on Bluesky’s board — but isn’t running the show like he once did at Twitter. “Jack doesn’t have unilateral power,” Graber wrote in a recent post on Bluesky. “I have the most control over this endeavor.”

Dorsey, who these days posts more often on Nostr, his other decentralized social media of choice, is at least an occasional Bluesky user. He recently took to Bluesky to share his latest thoughts on Musk and how he has handled the Twitter acquisition. The former CEO, who once said “Elon is the singular solution I trust,” said he thought Musk should have walked away from the Twitter deal, and that the company “went south” after his acquisition.

The service itself looks and feels a lot like Twitter. Bluesky defaults to a chronological timeline of accounts you follow, but there’s also an algorithmic “what’s hot” feed that surfaces popular posts or “skeets” as early users have dubbed them. It doesn’t yet have as much functionality as Twitter — there are no direct messages or video support, for example — but the interface is almost identical to Twitter.

Bluesky is also invitation-only, which has so far helped fuel its viral success. The platform began opening its waitlist more widely last month, and new users receive one invite code every two weeks (though some of the more prolific users get codes more often). Graber has said the invite system is meant to prevent spammers and others from easily gaining access to the platform, and to ensure it grows “organically.”

How is it different from Mastodon?

Both Bluesky and Mastodon are open source and decentralized, but there are some significant differences between the two. Mastodon is built on a protocol called Activity Pub, which has since been embraced by other platforms like Medium, Flipboard and even Meta.

Bluesky is building its own protocol, called the AT Protocol or Authenticated Transfer Protocol. As the company notes on its website, Bluesky, the app, is meant to show off what the AT Protocol can do, similar to how early browsers demonstrated the potential of the web.

According to Bluesky, one of the biggest differences between AT and other decentralized social networking standards is how it handles account portability. “With the AT Protocol, you can move your account from one provider to another without losing any of your data or social graph,” the company explains.

Right now, Bluesky itself is running the only instance of the platform. But just as Mastodon has thousands of servers available, there could eventually be numerous Bluesky servers run by other entities. That’s also where the emphasis on account portability comes in: it should make moving between servers fairly seamless, including taking your social graph with you when you move, which isn’t currently possible on Mastodon.

Bluesky is also taking an interesting approach to algorithms and moderation. On Mastodon, each server sets its own norms and moderation guidelines, which are enforced by admins. But while Bluesky’s team is to some extent setting their own norms for what’s currently acceptable, the app allows users to customize what level of moderation they want, ranging from “hide,” “warn,” or “show,” for things like hate speech, spam and impersonation.

Right now, there are some moderation labels that appear on posts containing things like impersonation, but Graber says the goal is for labels to eventually be community-led so that moderations can function independently of individual servers. Graber has dubbed the approach “composable moderation.”

Similarly, the platform is planning a customizable take on algorithms. Graber has said Bluesky wants to create a “marketplace of algorithms” so users can be in control of how their feeds are filtered.

Why is it suddenly so popular?

Like many other Twitter-like services, there’s been increased interest in Bluesky since Elon Musk took over the company. Its early ties to Dorsey and Twitter has also fueled the curiosity of those searching for a new platform.

But it wasn’t until Bluesky began opening more of its waitlist over the last couple weeks that it started to become more widely known. As the service approached its first 50,0000 users last week, more and more prominent Twitter users have joined. Representative Alexandria Ocasio Cortez, James Gunn, Chrissy Teigen, Rian Johnson and other celebrities have joined in recent days. So have other recognizable Twitter users like WeRateDogs, Dril, darth and Musk nemesis ElonJet.

It’s not just former blue checks though. Black and transgender voices have also found Bluesky welcoming. So have sex workers and shitposters. Needless to say, things have also gotten very weird, very quickly.

The massive influx of users exposed a technical glitch that soon became known as the “hellthread.” The glitch meant that long threads with lots of replies would break in the app’s main feed but users would continue to see notifications for new replies. “Just don’t reply to the thread to stay out,” Graber posted. Bluesky users, naturally, had other ideas. People not only kept replying, they tagged others into the phantom thread. At some point, users began dropping nudes into the hellthread, ultimately causing the app’s developers to block nudity from Bluesky’s “What’s Hot” feed.

Weirdness and nudity aside, Bluesky’s current popularity seems to be driven by both novelty of the service and because it’s so much smaller and simpler than its predecessor. The small user base and invite system has also so far mostly kept out trolls and bots and spam that tend to make Twitter a lot less usable for high-profile accounts or people from marginalized backgrounds. At a time when Twitter has reversed rules protecting trans people, unbanned Nazis and harassers, and algorithmically favors those paying for blue checks, Bluesky is a reminder of how good “old Twitter” used to be.

Will it last?

Just how long the good vibes will last is another question. Bluesky isn’t the first Twitter alternative to take off and see a surge in interest from former Twitter power users. Mastodon surged for months last year following Musk’s takeover of Twitter, and inspired high-profile Twitter users and developers to flock to the platform. But that growth seems to have now leveled off, and the number of active users has declined after months of growth.

Bluesky has some advantages over Mastodon: It’s easier to use and much more intuitive for Twitter users, assuming you can score an invite. But whether Bluesky remains as popular as it is now will likely depend on if the platform can sustain the same level of interest once it expands beyond the current invite system. Many viral apps start off as invite only (Clubhouse, for example) only to fade into the background once they are no longer exclusive and novel.

On the other hand, Twitter is still a mess and there is clearly sustained demand for a non-Musk operated alternative.