Maybe it's obvious, but it occured to me yesterday while working on a rumours table for my current campaign: make your rumours assertive. "A dragon landed north of the town last sunday", not "some people claim they saw a dragon landing north of the town." It may be true, or false, or anywhere in between, and it may come from any source; let the players investigate if they want more info.
@Sandra Oh, I do know what is true and what is not. Actually even most false rumours may lead to other hidden facts if investigated. My point is, when you hear something from the neighboring table at the pub, it usually is presented as fact.
Regarding Mershy and Harrioph, this is not exactly the same as the "some people" in my first post. In my current campaign I tend to let the players ask "who said that" or "who saw that" but I might give them the info along with the rumour.
I finally turned this into a blog post: https://the-dm.oook.fr/2020/10/04/about-rumour-tables/
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