Can I send private message to my users using PHP Facebook SDK? -

i create facebook application , need know if can send private message users have joined application. possible?

note: send messages to my users , not friends of users (i think not possible spam reason...right?).

asaik cannot send message, can open dialog user see + send message:

https://developers.facebook.com/docs/reference/dialogs/send/

(via http://facebook.stackoverflow.com/questions/2943297/how-send-message-facebook-friend-through-graph-api-using-accessstoken)