People's dividing lines between Projects and Someday/Maybes for items that are more Someday than Maybe are scattered throughout many threads. It might be handy to have a reference thread where we report/discuss our own dividing lines and how they are working for us.
My dividing line is that I designate as Projects multi-action tasks requiring action this calendar quarter, and if no action is possible, there must be a Calendar or Tickler entry. It is an artifact of a higher-level planning system. Rather non-canonical, I know.
Although this helps me maintain focus on my quarterly goals, I would only recommend it to someone who has that same focus problem.
I'm sure you all have more insightful comments than *that*!