I give out lots of rumors in my DF game. Here is how I do it.
First, I make up the rumors. I have a spiffy d30 with nothing else to use it for, so I use that for rumors. I write down 30 of them in a Word document, numbered. I use them to feed knowledge about the dungeon (depth, entrances and exits, inhabitants, etc.), warn of dangers, give out information about monsters, and especially to feed backstory that is tied to the current story (thus providing context and clues together). If I end up with more than 30, I just stick them at the end as replacements for next time.
Anyone who spends a week in town gets one rumor they pick up in the process, automatically. This means outdoorsy types who skimp out on upkeep by making Survival rolls and camping outside of town miss out. They save money (and have to make a relatively easy roll) but don't contribute to the knowledge base of the group.
Anyone staying in town can make a Carousing skill roll if they aren't occupied doing other things, like doing research, learning spells, or otherwise busy (taking a job for extra pay, say). Making the roll gets you one more rumor, and every two points you make it by gets you one more. If you've paid extra money over and above your normal upkeep for extra carousing, I give a plus to the roll. We've figured one normal carouse costs 15 sp (an extra 10%), so +15sp gets you a +1, +30 sp a +2, etc. up to +5 for +240 sp. (Vryce has upkeep of 150, plus 15 for Compulsive Carousing, and spends 200, so he gets a +2 to his Carousing rolls - more than 30, less than 60) The basic idea is, the better you are at being a garrulous and entertaining party-er and the more sober you can keep yourself in the process, the more you learn (and remember).
The players get to roll the d30 for their rumors. As they learn them I bold them in my document so I know they've been used.
After the session I go through the document and move the learned rumors to the bottom of the file under "Rumors heard" and then replace them as I think of good ones. I try to think of new rumors based on things they seem to care about - lots of gargoyle rumors came up after they started to spray money around on research on killing them and talked about fighting them, for example.
- These have been a lot of fun, and people love to roll the d30. They also love to complain if they get anything below a 21, because they may as well have rolled a d20. You could easily do this on another die system, but I prefer one big polyhedral to smooth out the chances. I'd hate to bell curve these and need to decide what rumor is rare enough to be a 3 or uncommon enough to be a 7 or common enough to be a 10 or 11. Just throw them all in a list and roll straight up. Not very GURPS but I have all these skippy dice from my other games . . .
- I bought my d30 so I could roll on some of the tables in The Dungeon Alphabet (review). I rarely use it for that, but I use it for rumors every game session.
- I don't mark the rumors (F) for false like old Mike Carr or Gary Gygax modules. It doesn't help me to know. It doesn't matter if it's true or not, really. Some might be absolutely true. Some might be off-the-wall false. But what isn't true now might be later (when I stock more of the dungeon), or be partly true, or might become true through the actions of the players. Others might be totally false but spur the PCs to valuable measures that prove helpful.
- If a duplicate rumor comes up, I'll either allow a re-roll (if that seems appropriate) or just amplify the rumor with more details. For example, last session someone got a rumor about the Good God vs. underground monsters, and then Inquisitor Marco rolled the same one - I told him he could confirm it was one of the church's teachings, and let him re-roll. It seemed appropriate. Other times I say simply, "Raggi heard the same thing, but the crazy old guy who told him said . . . " and give some extra oomph to it, made up on the spot or cannibalized from another unheard but related rumor.
- It's interesting when rumors come up. The rumor about a renegade gnome with goblinoid servants in the dungeons was on the table for a few sessions, but it didn't get rolled until after the PCs met (and left unmolested) a gnome with norker servants. A whole bunch of related historical bits came up all together last session. I don't plan this, although I will sometimes pick a rumor deliberately instead of rolling if it's extremely closely related to research they've done, and say "The sage says (blah) but the bartender at the pub said (blah blah) instead" and then just cross it off as a freebie.
- I assume people don't forget the rumors they heard, so the PCs can refer back to rumors they heard. These are busy people in the real world, and I'm not going to punish them for forgetting what that rumor about the well entrance was all about. The rumors are vague enough.
- Backstory is boring. Backstory that comes up in play, about things the PCs are digging into, is very interesting. Blah blah Baron Sterick's army consisted of blah blah - boring. "Baron Sterick's paychest for his army was never found, and it's probably still down there" - whoa, cool, how big was his army? Let's go find out! Would they have cared otherwise? Would you? Now it's important.
- Really big news (a mage's tower appears overnight in town, there is a war on, Smaug ate the town's mascot) is a freebie for everyone in town.
And that's how I do rumors, and why my players spend extra money (and sometimes extra points) on Carousing.