Mastodon

First released toward the end of 2016 under the AGPL, Mastodon [4] now has more than 1.5 million subscribers [19] and is expanding rapidly. The service is decentralized. Individual independent servers, or instances, each have their own user community. Managing the individual communities is the responsibility of the moderator of each instance. At the instance level, the admin also defines the access rights and content restrictions. The individual servers belong to the entire network of nodes.

The messages sent under Mastodon are called toots. They can be sent both within and beyond the boundaries of a community (i.e., to users of other communities or to a network of communities). The same conditions apply to receiving toots.

Users can only make their messages available to individual users or groups. Messages can also be marked as private.

The free software servers are based on Ruby on Rails, and the front ends use JavaScript. Communication between the two is managed by the ActivityPub protocol [20].

Getting Started

To use Mastodon effectively, you need an overview of existing instances and their thematic orientation. For this, you should open the https://joinmastodon.org page in your web browser, which starts a wizard. The wizard first asks you to specify a preference and choose a language. It then displays a list of matching communities (Figure 8).

Figure 8: In Mastodon, a wizard first presents the individual available instances.

After clicking on an instance of interest, the wizard sends you to the main page of this instance, where you can gain an overview of the community and join.

When registering, Mastodon asks for a nickname, an email address, and a new password and sends you a confirmation email. The account is enabled by clicking on an embedded link; you can then log in with the specified access credentials.

The instance directs you to a clear-cut window that keeps track of all communications and local posts and where you can enter your own messages, with a maximum length of 500 characters. Of course, you can also forward and share posts under Mastodon.

In the right pane of the browser window, a dashboard lets you configure various settings (Figure 9), mainly with the Settings | Preferences item, where you can make important security settings. You can edit your own profile, enable two-way authentication (Figure 10), and import and export files with a smartphone. The files can be saved and loaded in different categories as CSV files, which you will need if you want to join other instances.

Figure 9: The Mastodon communication window is separated into different functional areas.

Figure 10: Mastodon users can use two-factor authentication.

Because of the decentralized structure of the network, you can maintain a separate profile for each instance. Mastodon does not automatically transfer the contact lists and their rights settings from instance to instance. Once you have created a rights profile in a CSV file, you can import it into any new profile. In this way, you avoid having to specify blocked users or followers manually with the rights defined in each instance.

Own Instance

Companies with distributed locations might be interested in having their own Mastodon instance. The developers provide detailed documentation for this case [21]. Private users can also use this documentation to open and maintain a less restrictive instance. You don't even need your own dedicated server. Instance operators can offer the service through hosters, with Mastodon running on Ubuntu 16.04 LTS with Docker and a Nginx web server [22].

The application server can also work separately from the content with different cloud services. All you need is your own domain, at least 2GB of RAM, and the corresponding free capacities on mass storage.

Companies can install the GitHub-hosted project on a dedicated server if they want to avoid cloud operation. Mastodon supports the SMTP protocol: The service sends email messages to administrators when certain events occur, so they always have an overview, even during intensive use of the platform.