[$] Beyond microblogging with ActivityPub

ActivityPub-enabled microblogs are gainingpopularity as a replacement for Twitter, but ActivityPub is for more thanjust microblogging. Many other popular services also have open-sourcealternatives that speak ActivityPub. Proprietary services operated bycommercial interests usually deliberately limit interoperability, but usersof any ActivityPub-enabled service should be able to communicate with eachother, even if they are using different services. This promise ofinteroperability is often limited in practice, though; while ActivityPubspecifies how multiple types of contentcan be published, the kinds of content that can bedisplayed or interacted with vary from project to project.