As anyone who has ever worked in the field of creative fiction (of any sort... books, films, television, and even roleplaying games) can tell you, it is almost impossible to come up with a completely and totally original idea. This isn't necessarily a bad thing. As the folks at that time-sink of a wiki TV Tropes will tell you, old ideas are useful because they are recognizable. You don't have to explain every step of the Hero's Journey because people have seen it so many times that they feel comfortable with it.
The reason I bring this up is because I'm relatively new to Pathfinder, and especially new to Golarion. I have no intention of ever using the setting, as I have a well-rounded, deep, and exciting homebrew gameworld of my own that I've been working on since 1983, but it never hurts to look around, and who knows, maybe I'll find something I could adapt. You know how it goes, I'm sure.
So anyway, I've been poking around the wiki now for about a week, and after reading a bunch of articles, I couldn't help but notice something that I found really, really interesting: Golarion is amazingly similar to the homebrew fantasy campaign world.
The one I mentione just now. The well-rounded, exciting one I've been playing in since 1983. That one.
And when I say "amazingly similar", I mean "Wow... what are the odds that both worlds would have a cataclysmic event where a huge something fell from the heavens, smashed up one of the early empires, formed a centrally-located sea, and led directly to the creation of the drow" similar. This was just one example, but it was the one with the most direct similarities. There are many others. Seriously, its almost like one of the developers of this setting was in my gaming group sometime within the last 30 years and liked what they saw.
Now, before anyone gets up in arms, I assure you I am accusing NO ONE of plagiarism, stealing, or what-have-you. Not only is such an accusation baseless and stupid, its baseless and stupid as well. But it did strike me how often creative minds can come up with similar ideas independently.
So, as you go about your gaming life, be not afraid to do something you want to do, just because someone else has done it also. The trick, as I said, is putting your own unique stamp on things.
Thanks for listening.