If you connect to Pinterest with Facebook, it has multiple dialogs that show your complete list of friends (including those not using Pinterest) asking you to invite them. One is on the front page, and there is another at http://www.pinterest.com/find_friends/
This type of menu is only supposed to be possible for games that use Canvas by using the taggable_friends API, not for a website.
I see multiple questions here asking about how to do exactly what Pinterest is doing, but the response always seems to be it is impossible, the only supported way is to use the Send dialog (for a website not an app/game anyway).
It seems like they got some special permissions before from this thread: https://developers.facebook.com/bugs/146850488822600 Is their current build just another special permissions thing? I haven't been able to find anything stating that they have special permission, and it would be nice to confirm that considering it's not very convincing to say it's impossible when there's a high profile example of it.
I don't want the list to spam their friends, I still want to go through the Send dialog but it would nice to show a list of people that they can invite in a format that is shared with other social sites we have integration with.