Since its launch in October 2016, microblogging social network Mastodon has been gaining ground, reaching 1 million users as of December 2017. To many it's the anti-Twitter. Though much like it in appearance and feature-set, Mastodon places greater emphasis on safety and privacy.

It does this in large part by being decentralized and federated – its messages (called "toots") distributed across a number of independent servers with their own communities, interests and rules. But users are free to follow each other, favorite and boost (the equivalent of retweet) messages regardless of the server they're on. To mention someone, you just need to include their server as well as their username, much like an email address (so for example, if you're on Mastodon you can find me at @jh@mastodon.org.uk).

But Mastodon is just one example of this new breed of social network, publishing platform and website which makes up the fediverse – a loose family of sites that promote unfettered interaction across servers or even services, and which may just buck the trend of locking content behind the comparative walled gardens of Twitter, Facebook and their ilk.

"… it's not just the social side of Twitter causing upset …"

Hang around on Mastodon for any length of time and you'll see users passing comment on "bird site" – their disparaging term for Twitter. In part this is down to the direction the social network has taken as the home of increasingly polarized discourse between the left and right, which all too often descends into abuse or hate speech.

There's a view that, in particular, Twitter hasn't done enough to tackle the presence of Neo Nazis on its platform, whereas some Mastodon servers explicitly ban Nazi imagery and holocaust denial, taking cues from German law. A core feature is the ability to restrict certain toots to certain audiences, and another to hide content behind a warning if it's likely to be triggering in any way.

But it's not just the social side of Twitter causing upset. Recent changes to Twitter's API have compromised popular third-party Twitter apps like Tweetbot and Twitterific. As a result, the apps were forced to remove features like Wi-Fi timeline streaming, notifications for likes and retweets, tabs for activity and stats, and Apple Watch support.

Twitter claims these are necessary steps, sunsetting old, unmaintained parts of the API in the name of progress. But others see this as an attempt to pull users away from third-party apps and into its own, complete with promoted content, suggestions for users to follow, and perhaps most controversially, non-chronological timelines which prioritize tweets according to Twitter's own unknowable algorithms. Arguably, Twitter is increasingly funnelling users to determine what they see in its attempts to drive a profit.

"… Admins were empowered to take action and did …"

But Mastodon is by no means alone in attempting to decentralize the social web. Where Mastodon's posts are limited to 500 characters, social network Diaspora offers much longer posts which can be shared publicly, within particular social circles chosen by the user, or by tagging them according to subject matter.

In some respects Diaspora is to Facebook as Mastodon is to Twitter. But where Mastodon so far seems to have remained unsullied by dubious content, Diaspora hit difficulty in 2014 when members of Islamic State adopted the platform to distribute propaganda having had their accounts shut down by Twitter. Though the Diaspora was greatly concerned by the turn of events, it was powerless to take action, as control of any one Diaspora server (or "pod") falls to that server's administrator, who could be anyone.

"Each pod administrator has final say over the content hosted on their pod," the Diaspora team wrote on its blog at the time. "And we, and our entire community of members, work to help our podmins to keep the network healthy and growing."

To its credit, the team contacted pod administrators directly to highlight IS accounts. "So far, all of the larger pods have removed the IS-related accounts and posts," it said. It could be argued the episode highlights the strengths of a federated approach. Admins were empowered to take action and did. And though to its credit Twitter took action in that case, it's the exception more than than the rule so far as shutting down offensive content goes. If there's a lesson for potential users of the fediverse, it's not to stay well away but to choose well-used and well-moderated instances when signing up for services.

So far so social – but it's not just social networks adopting the federated approach. PeerTube takes a federated approach to video hosting and Funkwhale to audio. Meanwhile the services ownCloud and its offshoot Nextcloud apply the same principle to file-hosting a la Dropbox, but with a host of other features such as support for calendars, contacts, bookmarking, text editing and RSS.

Clearly some services are more demanding with respect to data transfer than others and so instances aren't necessarily free. For now, where tech savvy allows, the best bet may be to self-host where possible.

No one federated service is likely to be causing much of a stir in Silicon Valley boardrooms, but its their collective potential to become greater than the sum of their parts by encouraging interaction between services that is truly exciting, and it's a prospect that is very possible (and indeed already happening) thanks to standard protocols common to federated services.

"… by decentralizing content you deprive advertisers of a controlled and quantifiable audience …"

Arguably leading the charge is ActivityPub, a standard published as a formal Recommendation of the World Wide Web Consortium in January of this year. In a nutshell, content posted using one application can be liked, shared or commented upon from another, and users can subscribe to (or follow) each other's content across networks.

In a post that's well worth a read, software engineer and blogger Jeremy Dormitzer explains ActivityPub like so:

"It's a language that any application can implement. For example, there's a YouTube clone called PeerTube that also implements ActivityPub. Because it speaks the same language as Mastodon, a Mastodon user can follow a PeerTube user. If the PeerTube user posts a new video, it will show up in the Mastodon user's feed. The Mastodon user can comment on the PeerTube video directly from Mastodon. Think about that for a second. Any app that implements ActivityPub becomes part of a massive social network, one that conserves user choice and tears down walled gardens. Imagine if you could log into Facebook and see posts from your friends on Instagram and Twitter, without needing an Instagram or Twitter account."

Dormitzer makes a compelling case for the fediverse and ActivityPub in particular, painting a picture of a world wide web with content that is not only accessible to all, but social by its very nature, with likes, comments and the like bridging sites and services. But as he points out, success is by no means a given. For one, by decentralizing content you deprive advertisers of a controlled and quantifiable audience.

ActivityPub is by no means the only protocol in the fediverse. Diaspora is itself a protocol as well as a service which other fediverse social networks like Friendica and HubZilla support, effectively making those networks extensions of each other. Not all protocols are in competition, necessarily. The widely-used Webfinger protocol can be used to share personal information across the web, for example.

At the moment the fediverse feels like a scrappy insurgency, and for now that's very much its appeal. Whether it can tempt across mainstream web users (or indeed, whether it wants to) remains to be seen. And what that means for moderation, business models and the overall health of the fediverse is far from clear.

As far back as 2012, technologist Anil Dash published a memorable blog post, titled The Web We Lost, lamenting the demise of the open web and the rise of social networks as walled gardens with only semi-accessible content. In the fediverse, we have a glimmer of the possibility that that which was lost can be found – or more accurately, built again.