For example, "Let it be known that realm A declares war on realm B because so and so. Our cause is just because this and that." or "I, King of A, officially step down because so and so and plan to secede and do this and that." You know? The stuff that just happens and rank and file knights have no idea why if their top leaders are lazy/paranoid/uncaring/barely active (and they usually are).
Also a good platform for advertisement/recruitment of knights for specific causes (wars, reconquistas, etc.)