Deep Athelas, Chantmaster Extraordinaire

OK, here's the revised Rumormonger feat:

Rumormonger

Pick a locale. You are steeped in the rumors of that area.

Benefit:

You possess the bardic knowledge ability when in the chosen location. Before attempting to use bardic knowledge you may also declare that you are using the Rumormonger special ability. If you do, add half of your ranks in Gather Information [here 6, so half is 3] to your bard level when making a bardic knowledge check; that is, your bonus is your bard level + half the number of ranks in Gather Information + your Intelligence modifier [here, a total of +6]. Furthermore, an additional bonus is granted to common information: A check at DC 10 gets a bonus of +3, a check at DC 15 gets a bonus of +2 while a check at DC 20 gets a bonus of +1. The DC of any check should be made relative to the rarity of that information in the chosen location [here Sigil].

The drawback, however, is that the information gained by Rumormonger may not be correct. After declaring that you are using Rumormonger, the bardic knowledge check is made secretly. If it fails, the DM will provide false or inaccurate information; how false or inaccurate is entirely at the DM's discretion. There is absolutely no way for you to distinguish between true and false information gleaned by using this feat.

You may also attempt to spread rumors with a Gather Information check. This takes one full day during which you may not do anything else except eat and sleep, and requires full, unfettered access to the region (i.e. you can't be in jail). The DC associated with a given rumor is determined as follows:

• DC 10 -- involves a plausible charge about a well-known figure or institution; the kind of thing that even skeptic would say "well, it could be true". Or: a minor change is happening in the area; e.g. the mayor is planning to pass a law that will raise the ale tax by one copper.
• DC 15 -- involves a well-known figure or institution but somewhat alters their usual narrative; e.g. trying to get a paladin known as a lousy tipper. Or: breathing life into a common legend; e.g. drow have been sighted out in the Great Woods! Or: a major change will be happening in the area; e.g. the town guard will be going on strike if curfew is not moved to sundown.
• DC 20 -- drastically alters the narrative of a well-known figure or institution; e.g. a paladin with a sexual addiction. Or: a fundamental change is going to happen in the area; e.g. the plague is coming. Or: bringing something obscure (whether person, institution or legend) into the foreground; e.g. making sure everyone has heard of Cromyn the Three-Handed. [This is especially useful if you subsequently want to slander this thing.]
• DC 25 -- A wildly implausible rumor concerning a well-known figure, or an implausible rumor concerning an obscure figure.
• DC 30 -- An Olde Legende is back! The sky is falling! Run for your lives!

The more specific the rumor being spread, the higher the DC. In general, each additional increment of specificity should raise the DC by 5; thus, if it's important not just that the plague is coming, but specifically that the red-veined bloodscourge is coming on the Great Eastern Caravan Route, the DC check of this rumor should be 30, not 20.

If the check succeeds, the rumor will spread throughout the region within 1d6 + 1 days. You may spread up to 3 rumors per week. For each rumor beyond the first, however, you incur a cumulative -2 penalty on the Gather Information check; hence the second rumor spread in a week is at a -2 penalty, and the third rumor is at a -4 penalty.

Optional rules

At the DM's discretion, depending on how baroque you want to get:

1. Additional modifiers may be given for particularly juicy, salacious or otherwise cool twists on a given rumor. A rumor about a paladin having it off with a whore is one thing; that Sir Jonah is in fact deeply submissive and was seen by Her Ladyship's maid wearing a saffron-colored dog collar while salving a burn on his breast is (sadly, ever-so-sadly) the kind of rumor that spreads like wild-fire.
2. Plausibility varies wildly depending on the context. A rumor about armies marching on the chosen location would normally be DC 20 since it's a fundamental change to the region. If the entire region is at war, however, this rumor would be DC 15; and if armies were known to be in the area, it would probably be DC 10.
3. Another factor to consider is the willingness of people to believe a given rumor. Rumors latching onto current events -- a drow was just seen in the market buying provisions; the Gardner boy just died of a mysterious ailment -- should receive bonuses commensurate with their enhanced plausibility.
4. Means of communication can boost your Gather Information check when spreading rumors. Access to broadsheets, the Risvold Street Irregulars or what have you should grant appropriate bonuses.
5. Rumors tend to morph unexpectedly. If a rumor has penalties for being specific, the check is said to partially succeed if it exceeds the base number but fails against the augmented number. To use the plague example above, Hinsten gets a 24 on his Gather Information check. He has failed to focus the rumor on either the type of disease or the way in which it spreads; all the city has heard is that the plague is coming. Had he got a 27 on his Gather Information check he could choose either to ensure that the city believed it was specifically the red-veined bloodscourge, or that the city believed it was specifically coming via the Great Eastern Caravan Route, but not both.
6. The law of unintended consequences is never so great as when spreading rumors. The DM is encouraged to spend a few moments thinking about the consequences of, say, convincing a paladin's family that he was a murderer, or telling a city of a million that the plague is coming.