You can ‘collaborate’ now by “directly adding a reminder from the selected note by using the system wide sharing extensions.
Interesting; though I’m very interested in collaboration, I am most satisfied that Agenda is integrating with Reminders, and does with Calendars, as not everyone I work with wants to own Agenda, but most use Macs, and all can access calendars.
Please someone correct me if I am overstating/assuming too much here.