Of course it's been done before
Just about every successful initiative and project starts from a place of replication. The chances of being fundamentally out of the box over the top omg original are close to being zero.
A better question to ask is, "have you ever done this before?" Or perhaps, "are the people you are seeking to serve going to be bored by this?"
Originality is local. The internet destroys, at some level, the idea of local, so sure, if we look hard enough we'll find that turn of a phrase or that unique concept or that app, somewhere else.
But no one is asking you to be original. We're asking you to be generous and brave and to matter. We're asking you to step up and take responsibility for the work you do, and to add more value than a mere cut and paste. Give credit, definitely, but reject vemödalen.
Sure, it's been done before. But not by you. And not for us.