Great idea & execution! Any reason why you chose to post a "link" to the user's wall instead of something else? I've had more success (higher CTR to app and higher engagement on FB) from posting nice large graphics to a user's wall using the photos API. Make a POST to /USER_ID/photos.
Also, I haven't had much success using Facebook invites/requests or the Facebook App Center yet - would be interested to see what kind of conversion you can get.
Looks like you're posting a "link" with a photo attached (using "/feed"). I'm definitely seeing the graphic you're posting, just suggesting a different method/post type which may engage users better.
Thanks man, the goal is to get our product in front of more people. We convert very well when we get people to our site, so this seemed like a cool, fun way to do that
Also, I haven't had much success using Facebook invites/requests or the Facebook App Center yet - would be interested to see what kind of conversion you can get.