Some Rules of Common Courtesy When it Comes to Fanfiction and Taking Other People’s Prompts:
1. If someone else created an idea/prompt and posted it on their own blog, you don’t write something based on that prompt without first asking that person if it’s okay
2. If someone else created the idea/prompt and posted it on their own blog and they’re already planning to write something for that prompt, you ESPECIALLY should ask for permission to write your own take on it
3. If someone else created the idea/prompt and posted it on their own blog and they have not indicated that they’re okay with someone else taking that idea and using it as their own, you should assume that they would NOT be okay with you doing as such UNTIL you message them first and ask if they’re cool with you using their idea
4. If someone else created the idea/prompt and posted it on their own blog and they are making it known that they don’t want someone else running away with that idea, you are thereby not allowed to use it and you have no right to get pissy about it. It was their idea, not yours. Instead of getting upset with someone for wanting to keep and use their own prompt, maybe show some creativity and come up with your own idea.
Taking someone else’s idea without getting their permission first is PLAGIARISM, no matter how you try and justify it. Just because it’s fanfiction does NOT mean it’s suddenly okay to see a prompt created by someone else and go, “OOH, I LIKE THAT, I’M GOING TO WRITE IT!”
No. You ask the person who created the idea first. Maybe they’ll be cool with it. Maybe they planned to write it themselves. Maybe they don’t want someone else coming in and writing their idea before they even get the chance to themselves.
Stop Stealing People’s Fanfic Ideas Without Permission Just Because It Comes in the Form of a General Prompt 2k15.