diff --git a/FEDERATION.md b/FEDERATION.md
index ef331c2..27ee012 100644
--- a/FEDERATION.md
+++ b/FEDERATION.md
@@ -565,6 +565,10 @@ Requirements, suggestions and details:
   are, and it allows people to opt out of notifications if they previously
   commented on some topic but don't want to be in the discussion anymore. This
   makes it very easy for clients to correctly address comments.
+- The wording in the ActivityPub spec implies that `followers` is a property of
+  actors, and I'm unsure whether it's safe and compatible to use it with
+  non-actors. So until this point is discussed, the temporary proposed name for
+  the followers collection is `participants`.
 
 `GET /luke/outbox/A0O8l`
 
@@ -598,8 +602,6 @@ Requirements, suggestions and details:
 
 TODO:
 
-- `followers` is for actors, it seems, by the AP spec? So, what do we call the
-  collection of followers of a ticket?
 - `replies` and how the C2S object nesting depth proposal
 - Use `nonActors` in the example?
 - Content format? HTML? Markdown source? Tags? Referenced ticktes?