Ah, rumours. That venerable conceit, that ingenious method of imparting information to the players. Rumours are true, rumours are false. Rumours come on tables and charts, they come in the form of maps, they come from the old man in the tavern and the city guardsman who used to be an adventurer, before he took an arrow to the knee.
One thing you should realize up front: I'd never heard about rumours and their mechanics before discovering the OSR.
Sure, I knew the old rag about the old man in the tavern. I even purposefully started a campaign that way once. But quests are different from rumours. Before I found the OSR, I had never even considered rumours as existing, much less the mechanisms of their dispersal or their uses and pitfalls.
I don't know how this happened. Certainly it has something to do with never playing a version of D&D before 3.5, though I'm kind of surprised I didn't pick it up in the AD&D books on my father's shelves that I spent hours with.
Okay, no, I'm not that surprised; I was mostly into them for their cool pictures, especially of monsters. I was so into the monsters I actually read their descriptions.
Anyhow, now I'm in the position where I want, nay, need to give rumours to my players. So what do I do?
Obviously, I construct a rumour chart and roll a d20 (or d30), and for getting fancy I allow carousing to increase the chance or number of rumours you get.
So let's talk about Hommlet. Hommlet is a small town that mostly wants to keep its head in the sand, with some bad elements mixed in trying to tear things apart. The townsfolk don't know much and they don't want to know much about the Temple; sure, there are some folks that do, but the PCs should be talking directly to them instead of just rolling on a chart if they want that information. Information that should come from specific sources shouldn't be part of a rumour mill.
What sorts of rumours can they pick up in Hommlet, then? The Moathouse is right down the way; most everybody knows about it and knows at least a little of its history. Those living on the southeast side of town might know a little about the comings and goings thereabouts, but not much. The villagers' information on the Temple of Elemental Evil is even more sketchy. Talking to Burne or Jaroo directly might yield fruit, but just drinking at the inn isn't going to get you much more than the hopeful talk of other adventurers.
If the PCs spend the week in Hommlet, they don't get a rumour for free. Carousing can get you one rumour, though.
Nulb, on the other hand, is a hotbed of activity. Seriously, just look at the banner; you've never seen a more wretched hive of scum and villainy. (Unless you're a Martial Artist who took the Wizard lens. Then, maybe.) PCs who stay in Nulb get one rumour for free. If they carouse, for each two points they succeed by, they get another, until the chart's dry for that week.
Simple. Easy. Another distinction between the two villages. I might even institute a Nulb-specific "if you fail at carousing, something bad happens" chart, though not as severe as that link, methinks.