I just found these guidelines at TechCrunch:

• No incentives may be given to a member for sending a message, bulletin, comment, or any other form of communication. This includes “points,” “bucks,” increased standing, or even features within the app.
• It must be very clear to a member what they are sending, when they are sending communication. “Share with friends” is not sufficient messaging, the link must state “send comment,” “send bulletin,” and so on.
• The “no popups” rule we have had in place since day one applies to messaging windows. This means no more popping up a messaging window the first time someone tries to use an app. No popping up messaging windows without a user clicking on a very clearly marked link.

Sounds like they want the apps to appear as if they’re part of a Myspace experience, not add-ons. While I can see the intent of the “incentive” rule, what about games? The whole point of most online games is to “increase standing” in some way, to win the game, right?