I recently received this question:
'I have a great idea for a resource. I think it will be great and sell really well. But I am worried about talking about it too much in case other people catch on to how great it is and steal my idea. How can I promote it to only teachers that buy and not other sellers?'
This is quite a strange question in that the answer isn't really a straight forward answer. It is more of a shift in mindset.
So some points from this question.
1 - Sellers are also your buyers - don't assume that because a teacher lists their own products they will have no use for yours in their classrooms. Teachers are busy people and teacher authors even more so! So no, even if there was a way (which I'm pretty sure there isn't) you shouldn't only market to non-sellers.
2- Ideas are not copyright - even if your idea is truly original, you don't own it. You only own the execution of that idea. For example writing a book about a young boy that is a wizard is not a new idea and anyone is allowed to do that. /using the harry Potter characters and story lines is not ok.
3- PROBABLY THE MOST IMPORTANT this wouldn't be a terrible thing. - Your resource idea being so great that it sparks other similar types can really help you. If you invented exit tickets for example. You would be the only person shouting about these great things, it would be up to you and you alone to share this great resource idea with the world and you wouldn't reach many people (in comparison to how many teachers need to use them). However if somebody else sees your idea and makes their own exit tickets, they are also going to start telling everyone about this great resource. Soon lots of teacher want exit tickets and when they come searching yours are the first and will have the most different types (because you have been doing it longer). Everyone else that makes them is advertising your product! It is also good to have lots of options for buyers. If you make lots and lots of your exit tickets but you haven't got an animal theme, the potential buyer that wants an animal theme might just give up and go away. If however someone else has animal themed ones, the buyer purchases them, uses them and loves them. Now they will come back looking for more types of exit ticket and this time they might buy yours. That is a customer that would have just gone away never to buy again.. Do you see?
So over all... Don't sweat it. If your product is that good, (which I am sure it is) it will succeed!