Here’s a breakdown of tools that use both or similar concepts, and how they differ:
1. Discourse (Forum Software)
Join: Become a member of the forum.
Subscribe / Watch / Track: Follow individual topics or categories for notifications.
✅ Clear separation between identity/membership and content following.
2. GitHub
Join: Become a collaborator or team/org member.
Subscribe: Follow repositories, issues, or discussions.
✅ Used for both org-level participation and fine-grained interest.
3. Matrix / Element
Join: Enter a room (you can now post).
Watch / Notify: Set notification preferences without participating.
✅ Join is about access; notification settings are subscription-like.
4. Slack / Discord
Join: Enter a workspace or server.
Subscribe: Follow specific channels or threads (via notifications or starring).
⚠️ Not always called "subscribe," but same behavior.
5. Reddit
Join: Participate in a subreddit (technically optional now).
Subscribe: Follow subreddit to get it in your feed.
⚠️ Join = subscribe for many users; posting allowed even without joining.
Semantic Difference
Join → I want to participate (write, comment, collaborate).
Subscribe → I want to follow (read, get updates, stay informed).
Relevance for Seed Hypermedia
If you're modeling community dynamics in Seed:
Use Join for participation rights or identity-related collaboration (like co-authorship or commenting).
Use Subscribe for passive following of a Site or Document — ideal for readers or lurkers.