The Mastodon community worries about whether the new EU copyright directive (which won’t enter into force for 2 years) will mean upload filters being necessary for the use of the ActivityPub protocol.
I can’t logically see why that would be, but only because I don’t compare Mastodon to e.g. Twitter or Facebook. Yet if you do then the worry is logical I suspect.
Mastodon is a server and a client for the ActivityPub protocol. In a fully distributed instance of Mastodon you would have only a small group of users, or just one. This is the case in my Mastodon instance, which only I use. (As yet the Mastodon universe isn’t very distributed or decentralised at all, there’s no long tail.)
The ActivityPub protocol basically provides an outbox and inbox for messages. In your outbox others can come get messages you make available to them and your server can put messages in your outbox into someone else’s inbox itself.
The Mastodon server can make what you put into your outbox publicly available to all that way. Others can put messages for you in your inbox and the Mastodon client can show publicly what you receive in your inbox.
But making anything public isn’t necessary at all. In fact I don’t need my public facing profile and message timeline on my Mastodon instance at all. They are non-essential. Without such pages there’s no way to argue that the messages I receive in my inbox are uploaded by others to a platform, and falling within scope of a potential need for an upload filter.
My Mastodon instance isn’t a platform, and the messages others send to it aren’t uploads. The existence and form of other ActivityPub clients and servers demonstrates that neatly. I currently send ActivityPub messages from my weblog as well, without them being visible on my blog, and I can receive them in my Mastodon, or any other AP client without them being visible for others, just as I can read any answers to that message on the back-end of my blog without it being visible to anyone but me and the sender(s). Essentially AP is more like one-to-one messaging with the ability to do one-to-many and many-to-many as well.
The logical end game of decentralisation is full distribution into instances with only individuals or tight knit groups. Federated where useful. The way the Mastodon client is laid out (sort of like Tweetdeck) suggests we’re dealing with a platform-like thing, but that’s all it is: just lay-out. I could give my e-mail client a similar lay-out (one column with mail threads from my most contacted peers, one with mails just to me, one with all mails sent through the same mail server, one with all mails received from other mail servers by this one.) That would however not turn my mail server plus client into a platform. It would still be e-mail.
Mastodon’s lay-out is confusing matters by trying to be like Twitter and Tweetdeck instead of being its own thing, and I posit all ‘upload filter’ worries stem from this confusion.