I'm creating a a social networking application on the Facebook platform and I need some way of allowing my users to communicate with each other to find out more about each other. After doing some research on SO it seems sending private messages is a very popular topic, but so far the most promising option for us seems to be this - Send private messages to friends - which is a pop-out JS client which unfortunately only allows you to send posts to your friends.
I actually find this very odd seeing as it appears that I can click on ANYONE'S profile and go to "send message" and send them a message WITHOUT permission, but there are no options to send messages between users of your app even WITH their permission!
1) I have seen Facebook applications which provide contact between their users such - Yoke and other dating applications - how do they do it? Are they writing their own php messaging systems?
2) Is there anything stopping me from sending messages to a users account using their facebook email address? This will obviously allow people who aren't your friends to send emails to you.
Thanks for reading :D