
Wonderstell |

So here's what the d20pfsrd has to say about the Shaken condition from the Demoralize action.
You can use this skill to cause an opponent to become shaken for a number of rounds. This shaken condition doesn’t stack with other shaken conditions to make an affected creature frightened. The DC of this check is equal to 10 + the target’s Hit Dice + the target’s Wisdom modifier.
Success: If you are successful, the target is shaken for one round. This duration increases by 1 round for every 5 by which you beat the DC. You can only threaten an opponent this way if it is within 30 feet and can clearly see and hear you. Using demoralize on the same creature only extends the duration; it does not create a stronger fear condition.
Fail: The opponent is not shaken.
While I understand that Demoralize won't stack with itself, the PRD lacks the first part about demoralize not stacking with other fear effects, and I've read that this part got introduced then redacted.
Is this true, or is d20pfsrd correct that Demoralize won't stack with anything?
Wonderstell |

The PRD is a rules source. Use that.
d20pfsrd.com is a third party site. It is not a rules source.
That, I know.
The problem is that the PRD is really awkward to navigate, and I've experienced that the information on the PRD sometimes is spread out across multiple sources.So even though I easily find the Intimidate page on the PRD, I can't tell if the other half of the information is hidden in some obscure errata on fear effects or not.
Which leads me to the rules forum. The missing sentence from the PRD is supposed to be missing then?

Saldiven |
It was a Core Rule Book errata from several years ago that Paizo has never edited into the PRD.
"Page 99—In the Intimidate skill, add the following
sentence after the first sentence of the Demoralize
paragraph:
This shaken condition doesn’t stack with other shaken
conditions to make an affected creature frightened."

avr |

As far as I can tell the PRD doesn't get errata added, or even typos specific to it corrected. It may be a good source in theory but unless you're willing to accept errors like spellcraft being used to avoid failing to cast a spell when damaged (as opposed to concentration checks) then it shouldn't actually be used as a rules source.

Helpful Harry |

Skill unlock for intimidate could help if allowed.
5 Ranks: If you exceed the DC to demoralize a target by at least 10, it is frightened for 1 round and shaken thereafter.* A Will save (DC = 10 + your number of ranks in Intimidate) negates the frightened condition, but the target is still shaken, even if it has the stalwart ability.
10 Ranks: If you exceed the DC to demoralize a target by at least 10, it is panicked for 1 round or frightened for 1d4 rounds (your choice) and shaken thereafter.* A Will save (DC = 10 + your number of ranks in Intimidate) negates the frightened or panicked condition, but the target is still shaken, even if it has the stalwart ability.
15 Ranks: If you exceed the DC to demoralize a target by at least 20, it is cowering for 1 round or panicked for 1d4 rounds (your choice) and frightened thereafter.* A Will save (DC = 10 + your number of ranks in Intimidate) negates the cowering, panicked, and frightened conditions, but the target is still shaken, even if it has the stalwart ability.
20 Ranks: If you exceed the DC to demoralize a target by at least 20, it is cowering for 1d4 rounds and panicked thereafter.* A Will save (DC = 10 + your number of ranks in Intimidate) negates the cowering and panicked conditions, but the target is still shaken, even if it has the stalwart ability.

EuphoriaStrides |

Wanted to hop in and say that, as the official rules source, aonprd is preferred to d20pfsrd.
It was a Core Rule Book errata from several years ago that Paizo has never edited into the PRD.
"Page 99—In the Intimidate skill, add the following
sentence after the first sentence of the Demoralize
paragraph:This shaken condition doesn’t stack with other shaken
conditions to make an affected creature frightened."
It never made it into the PRD because it's not in the Core Rulebooks. Even if at one time proposed as errata, Paizo made the decision to not include it in later printings The 6th (and most recent as of 2013) printing of the Core Rulebook has had this change removed, so that it clearly reads:
Demoralize: You can use this skill to cause an opponent to become shaken for a number of rounds. The DC of this check is equal to 10 + the target’s Hit Dice + the target’s Wisdom modifier. If you are successful, the target is shaken for 1 round. This duration increases by 1 round for every 5 by which you beat the DC. You can only threaten an opponent in this way if it is within 30 feet and can clearly see and hear you. Using demoralize on the same creature only extends the duration; it does not create a stronger fear condition.
Cut and dry: That line is incorrect on the d20pfsrd; you can stack the shaken from demoralize with other shaken conditions to make an affected creature frightened. That is the general rule and there are no specific exceptions, so it is in use.
If you're interested in some history, this line was first discussed by Joshua J. Frost and Jason Bulmahn in 2009. You can find that here. Primary sources are since removed; thanks Paizo.
Specifically, Frost and Bulmahn both agreed that demoralize would not stack with itself, only extending the duration.
Note: This line made it into the core rulebook.
Someone then asked if that meant demoralize-shaken couldn't be upgrade by other sources of fear, which Frost (and not Bulmahn) agreed to.
Note: This is NOT in the core rulebook.