Facebook is continuing its war on Facebook apps that push the limits on acceptable user interaction. Last week it was Slide’s Top Friends App, which it briefly suspended. Later Facebook also suspended another popular app, Social Me.

This time they’re targeting Slide’s rival RockYou and their Super Wall application, which tends to have a lot of spammy user content. But instead of shutting down the application wholesale, they’ve simply turned off the viral components of the app – invitations, notifications, etc.

The consequences have been just as dramatic. A month ago Super Wall had 2.4 million average daily users. Today it’s 600,000 and falling fast.

RockYou CEO Lance Tokuda confirmed that Facebook had shut down features of Super Wall, but says they’re working with Facebook to fix the issues and expect things to return to normal soon.

One thing is clear in all this: Facebook is serious about slapping down app developers who go too far in their efforts to grab new users.