When you’re trying not to make your hints too obvious, or you want to give people a cross-section of what’s going on in a location, sometimes just one rumor isn’t going to do the job. Instead, you’ll want a rumor cloud: a set of rumors with varying levels of truth and relevance. I find the best use for these is when you’ve got a non-targeted rumor search—someone looking for everything that people are talking about rather than going after a specific subject.
When I’m doing a rumor cloud in a game, I usually start by figuring out the main set of subjects and messages—the rumors that will in the end be the most relevant to the characters (if they can figure out that they’re the ones, anyway). This doesn’t mean I make them the first, nor the last, unless it’s really important that the group Get It quickly; I prefer tucking them in the middle somewhere. Usually, I’ll have one really big primary and a few optional but interesting secondaries. For this example, let’s say I begin with the primary message “There is something decidedly wrong with the pigeons in this city.” I’ll want to build at least one rumor around that.
Then I figure out what my more optional messages are. If I plan on later bringing in an agent of another vaguely inimical power, I’ll want to throw in a reference to them (usually in terms of a very vague description) being somewhere on the edges. If another band of recurring characters has been through, I might drop a brief reference to someone seeing the most distinctive of them doing something characteristic.
Somewhere in the process, I’m going to think about the source. The way most of my groups work, I usually hit the source at about this point—I’ve planned what rumors I’m going to drop them ahead of time, and they’ve just found someone to ask. This is when I start tweaking my messages to fit—how knowledgeable is this person? What sort of voice do they have? Are they the kind who are going to be most concerned with the fact that for some reason the pigeons are only fouling a very specific set of statues? Or with the fact that the town guards are all being put through extra slingshot training? Or with the tendency of the birds to all gather in circles around improbable locations, or to descend on spilled loads of grain silently and with no fighting whatsoever over the food? Have they actually met, or even seen, the agent of the vaguely inimical power to be dealt with later, or are they just talking about their cousin’s run-in with some oddball in veils who looks too thin to be real?
Then I throw in the fluff. Usually, I’ll come up with something that would matter about the local setting (laws, vague politics, rabble-rousers and scandals), and something from the source’s direct acquaintances—raises in their workplace, speculation on who the boss is sleeping with, questions on whether the milkman has been skimming again, that sort of thing.
Figuring it out? That’s up to the characters.