Automattic has acquired the ActivityPub plugin for WordPress from German developer Matthias Pfefferle, who will be joining the company to continue improving support for federated platforms. Pfefferle, who is also the author of the Webmention plugin, said his new role is to see how Automattic’s products can benefit from open protocols like ActivityPub.

In 2021, Automattic CEO Matt Mullenweg indicated that he would be interested in having Tumblr support the ActivityPub protocol for a greater level of interoperability across networks like Mastodon and others using the same protocol. That is still in the works, but WordPress sites already have this capability through the plugin.

“ActivityPub and a lot of other Open Web Plugins (like the Webmention plugin) were spare time projects, so I was not looking for an acquisition,” Pfefferle said.

“When Matt announced that Tumblr wants to implement ActivityPub on Twitter, I asked why not WordPress, so I came in contact with Automattic and they offered me the opportunity to work full time on the plugin and other Open Web projects.”

The ActivityPub plugin makes it possible for readers to follow a WordPress site in the fediverse using the ActivityPub protocol. This includes Mastodon, one of the most popular platforms using the protocol, and other platforms like Pleroma, Friendica, HubZilla, Pixelfed, SocialHome, and Misskey. For those using Mastodon, this plugin will automatically send posts to the network and replies to it will become comments on the post.

Last March, the ActivityPub plugin had just 700 users. Today it has grown to more than 2,000 active installs. Although it is not yet widely used, it has gotten more exposure since Elon Musk bought Twitter.

“Thanks to Elon Musk, the number of downloads from my ActivityPub (WordPress) plugin and my followers on Mastodon have increased at least tenfold!” Pfefferle said in a post on his blog in January 2023. “This inspired me to work more actively on the plugin again and some great changes came about.”

Most recently, Pfefferle added a new onboarding screen with recommended plugins, added the published date to author profiles, and added outgoing mentions, among other features.

Pfefferle said he thinks the idea of the acquisition is not to have the protocol merged into core, but to “guarantee that it will stay open source and to maybe make it a canonical plugin.”

As more social networks unite on open protocols, it won’t matter where you choose to create your home on the web. Interoperability between apps allows people to post from whatever network they enjoy, creating a richer, more diverse web. Automattic’s support of the ActivityPub plugin ensures WordPress’ place in the fediverse, where blogs will not isolated islands but rather interconnected as many were in the early days of blogging. Pfefferle’s work embodies these ideals.

“I think my drive was always to build an alternative to the big walled gardens of Facebook & co,” Pfefferle said.

“I fell in love with the idea of blogging and the spirit of the Web 2.0 movement and tried to keep the idea alive. I worked on several WordPress plugins and participated in several movements (DiSo, DataPortability and others) starting in 2007.

“It is so exciting to finally see such a big interest in Open and Federated technologies!”