I rarely let others apps access my facebook account, so I don't know what exactly you do. Which can be a marketing problem since people like me would never sign up till they saw what the app actually did.

Which brings me to your description: "Simply double click on the map and we will automatically add details to it and share it."

What details? With whom?

I would suggest that you also create a web-page with some screen shots and some example use cases so that the value proposition is much clearer.

best of luck!