Manos,
It's likely that they are using the newer Request 2.0 system, introduced by Facebook earlier this year to manage invitations. We're still using Requests 1.0, but plan to upgrade in the 4.1 or 4.2 release. Requests 1.0 does not allow us to see the number of users that were invited, but 2.0 does.
Either way though, using incentives for invitations is against Facebook's terms of service for applications, so we likely wouldn't be including that functionality when Requests 2.0 is supported. Specifically, IV.1:
You must not incentivize users to use (or gate content behind the use of) Facebook social channels, or imply that an incentive is directly tied to the use of our channels.
Social Channels is defined as:
By "Facebook social channel" we mean Application Info Section, Page Tab, Feed, Requests (including invites), inbox attachments, Chat, Cover, Bookmarks, or any other feature of a user profile or Facebook communication channel in which or through which an application can provide, display, or deliver content directed at, on behalf of, or by permission of a user.
developers.facebook.com/policy/
Violation of terms can mean banning of your application. For us, it could mean a lawsuit by providing the means for many users to violate the terms, and it's not something we'd be doing.
Hope that explains,
Alex
Any rules and plugins with Alpha UserPoints Component?
