How does RockMelt send Facebook messages?

Everything I've read says that you ca开发者_StackOverflown't send messages but in RockMelt you can send your friend a beta invite through Facebook messages.

Are they using a preview of the Inbox API? Is there another way they're doing this?

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This was taken from an answer on Quora that Eric Vishria the CEO of Rockmelt said:

"If a user wants to invite a friend who has not signed up on our site, we generate a download link, and pre-populate a Facebook message (in our own UI) that the user can edit/tailor and click Send, or copy and send via some other means (email, chat...).

We do not auto-send Facebook messages and the messages aren't from us, they are user to user.

If a user invites a friend who has signed up on our site (via the "Hook 'em up" button) that sends a notification to our backend that a user has been hooked up and we send that friend an email that such and such user has hooked them up. We are able to do this because when users sign up on our website, they connect via Facebook and authorize our application to send them email.

We spent a lot of time making the system not spammy (no auto posts to feeds, no automatic emails, etc....) where invites go to people who want them or users have to take an explicit action to tell their friends about it."

http://www.quora.com/What-Facebook-permission-enables-an-app-to-send-user-to-user-messages?redirected_qid=97754

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To send a message to a friend you can use the Send Dialog, similar to the Feed dialog that will post to the wall but it lets the user select one or more friends and send a message: https://developers.facebook.com/docs/reference/dialogs/send/