To whom it may concern:
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.
(After the critical success of part II, and the strong box office sales of part III in spite of mixed reviews, will part IV finally see the June Open Thread jump the shark?)
There's a general rule in writing that if you don't know how many items to put in a list, you use three. So if you're giving examples and you don't know how many to use, use three. Don't know if that helps, but it's the main heuristic I know that's actually concrete.
I'm not sure I follow. Could you give a couple more examples of when to use this heuristic?