In my app, I can send the apprequests to my friends via FB api, and they can receive the Notification on iOS Facebook app. But here is a difference between "apprequest" and "postToWall". If I posted to my friend's wall something via Web, my friend would receive "Push notification" on his iPhone immediately. If I sent the apprequests to him, he wouldn't receive "Push notification" and just only "Facebook notification". Moveover, he needs to run the iOS Facebook app to update the data to receive the "Facebook notification".
Does anyone know this ?