Projects
A project links existing records around a piece of work — it never forks them.
A list gathers existing records for one piece of work — this cohort, this campaign, this review round. The + button opens a record picker; adding a record to a list links it, and removing it from the list never deletes the record.
Lists carry their own columns on top of the record’s attributes, so per-process fields (a stage, a note, a decision) live with the process instead of polluting the object.
The associations panel shows what else a record is connected to, and list-level notes hold the discussion that belongs to the list rather than to any one record.