The Threads decentralized protocol ActivityPub, what makes it special?

Original author: Jaleel, BlockBeats 

Original editor: Jack, BlockBeats

This morning, Threads was officially launched, making it the new app released by Meta following Facebook, Instagram, and WhatsApp, directly competing with Twitter. Not only is Threads named after one of Twitter's features, it also bears a strong resemblance to Twitter, emphasizing public conversations. Some tech experts have even referred to it as a "Twitter killer."

On its first day of launch, Threads had impressive data performance. Mark Zuckerberg stated that within 4 hours of launching, there were already over 5 million registered users, and within 7 hours, the number increased to over 10 million registered users.

It is worth noting that prior to its official launch, the app's photo preview displayed in the Apple App Store led many users to speculate that Threads could be logged in using their Instagram accounts. During a company-wide meeting last month, Meta executives revealed that Instagram Threads would be integrated with ActivityPub, a decentralized social media protocol based on Mastodon. This also means that Threads' content can potentially be used across multiple servers, and Instagram usernames, followers, and other account information can be automatically migrated to the new Threads app based on user demand.

In the login interface of Threads, we can clearly see how Threads works. In future versions, it will join a new type of social media network called the federated universe, allowing users to follow and interact with each other on different platforms such as Mastodon.

What is the ActivityPub protocol?

Speaking of the decentralized protocol used by Threads, ActivityPub, many people may not be familiar with it, but when it comes to the federated social network Mastodon, more people know about it.

At the end of last year, when Elon Musk laid off a large number of employees and modified Twitter's verification policy, causing a lot of chaos, Mastodon was the biggest beneficiary. Mastodon, which had accumulated around 500,000 active users before Elon Musk acquired Twitter, suddenly saw an influx of a large number of "refugees" escaping from Twitter. At its peak, it was gaining over 130,000 new users every day. In early December last year, the number of active users reached 2.5 million. After January this year, the number of active users dropped to 1.8 million, but still significantly higher than Lens and Nostr, which are protocols.

Mastodon's user base grew rapidly, and many celebrities also found a "new home" on Mastodon, which caught Elon Musk's attention. Twitter started banning links to Mastodon. In a Twitter Spaces, Elon Musk directly said, "Fucking post Mastodon all goddamn day long, I don’t care."

In the dispute of users fleeing Twitter, Mastodon seems to be the biggest winner. Eugen Rochko, Mastodon's founder and CEO, is a German programmer. According to the data he shared, Mastodon's active user count increased by 294,000 over the weekend, and the volume of activities published doubled.

It is worth mentioning that Phil Daian, a member of the Ethereum Foundation, operates an encrypted community called cryptodon.lol on Mastodon, and Vitalik has also joined.

At the same time, many people are not optimistic about Mastodon, believing that Mastodon is a good product, but it doesn’t represent the future of social networks. The protocol that represents the future of this field is ActivityPub.

Returning to our main topic, both Threads and Mastodon use and are based on the ActivityPub protocol. What makes them special?

Allowing users to navigate between islands

In the social future outlined by traditional social media giants, our Twitter account data is controlled by Twitter, Instagram account data is controlled by Instagram, and Youtube account data is controlled by Youtube. Each social media company is an isolated island, and each social media platform requires a separate account registration. Social media companies cannot exchange account data.

ActivityPub solves this problem in a simple and direct way: each server (instance) functions similarly to an email server, helping users send and receive messages, and hosting identities. It standardizes communication between servers, enabling interconnectedness between freely joining servers. It also standardizes communication between clients and servers, allowing users to access different servers on the same app. This provides both server administrators and users with a great deal of freedom.

This implementation allows social networks using the ActivityPub protocol to navigate between different islands.

Looking back over the years since the birth of social networks, there have been a series of protocols emphasizing openness: OStatus, pump.io, Open Social, Pubsubhubbub, WebFinger, ActivityStreams, XMPP, RSS, OpenID, and many more, most of which are not well-known to people. During certain periods of time, even some tech giants have supported these protocols.

The design concept of ActivityPub can be traced back to the birth of social networks, with the initial idea coming from Fediverse. The idea behind Fediverse is also very simple: a group of servers forming a decentralized network, exchanging messages with each other. This idea has led to the development of different software and protocols such as GNU social, OStatus, Mastodon, and so on. It can be said that ActivityPub has accumulated nearly twenty years of experience in exploring distributed social networks.

The first version of ActivityPub was released five years ago. After drawing lessons from the experience and design of software like GNU social in the Fediverse, as well as protocols like OStatus, it became a recommended standard of the World Wide Web Consortium (W3C). The W3C is essentially the governing body of the Web, responsible for supervising protocol standards. ActivityPub defines a decentralized social network protocol for client applications and the servers connecting them. The benefit to users is the interoperability between services adopting this protocol.

Specifically, for example, Flipboard and Medium have also established a Mastodon server on ActivityPub and have started inviting some users and content creators to post on the main platform. As long as the servers comply with ActivityPub, anyone can follow my Flipboard and Medium accounts from Mastodon, without needing to create an account or download a new application.

At the same time, if you like a post from Flipboard that comes from ActivityPub, you can embed this post on a Flipboard page, or even display it within the original creator's Mastodon application. After leaving a comment, the content will appear as a reply from Mastodon.

This is not just simple content embedding, it is true interoperability.

Furthermore, if Threads and Mastodon achieve intercommunication, deleting a post on Threads will not be visible on Mastodon. This is because a delete event will be transmitted to other ActivityPub instances, but if an instance does not support delete, the content can still be retained.

In addition to Threads and Mastodon, there are currently other social networks using the ActivityPub protocol, such as: Nextcloud, a federated service for file hosting; PeerTube, a federated service for videos; Friendica, a social networking software that implemented ActivityPub in version 2019.01; Mobilizon, an event planning software by Framasoft; Pixelfed, a federated photo-sharing platform similar to Instagram; Pleroma, a low-resource microblogging platform compatible with ActivityPub; Misskey, an open-source decentralized microblogging service.

Of course, currently, ActivityPub is far from perfect and has significant room for improvement. It often encounters errors and may even be suppressed under corporate interests or malicious attacks. In the race to reshape social media, apart from ActivityPub, there are also many participants, such as Artifact and Substack Notes, who have established their own closed platforms. Jack Dorsey, the co-founder of Twitter, has also supported new social protocols like BlueSky and Nostr. In the Web3 community, the popular social protocols Farcaster and Lens have also emerged.

All these emerging protocols hope to build their own open protocols and lead the social race. But why did Threads, which comes from Web2 giants, choose ActivityPub as its protocol?

Why did Threads, born from Web2 giants, choose ActivityPub?

First of all, what we can think of is that using ActivityPub, especially the communication standard between servers, can expand the existing social network of Meta and help communicate with other servers, allowing users to reach more people.

Liu Guo, co-founder of Matters-lab, very much agrees with this viewpoint. In his opinion, ActivityPub is currently the most mature and widely used decentralized social protocol. As a newcomer, Threads can make good use of the network effect that ActivityPub originally had.

In a conversation with BlockBeats, Liu Guo said, "Compared to several other similar decentralized protocols, such as Nostr and AT Protocol, ActivityPub wins primarily in terms of maturity, and it is also a w 3 c recommended standard. ActivityPub has many clients and a very comprehensive vocabulary that can be used to define almost all product logics, and its mental model is also very simple (actor model). Compared to other ActivityPub clients, Mastodon mainly has slightly better UI/UX and a way to integrate other protocols in an appropriate manner (such as web finger)."

Other than that, what other reasons led Threads, which came from a Web2 giant, to choose ActivityPub? Liu Guo believes that Meta is also aware that users care about privacy and data ownership, especially after the acquisition of Twitter, so they will choose a decentralized social protocol.

So, what does Threads' choice of ActivityPub mean for decentralized social protocols or web3 protocols?

Liu Guo believes that this is a good reminder to return to the essence. It seems that Meta is very clear about what users need. Users need a good user experience and a social protocol that can connect multiple clients, and all of this does not require blockchain. Blockchain can provide a good identity system, but it will only be useful to users when it is linked with off-chain social protocols, which is already a relatively mature field and approach.