Actually the one thing you can't turn off in your news feed is to receive app notifications. The person who adds the app can turn of sending them, but I can't turn off the flood of app messages in my incoming news feed.

Also, even if you disable the ability for the app to publish items in the news feed, it still publishes the add/remove notification. You have to remove that one manually.

As a user, the cluttering of the news feed is my biggest frustration with the new platform--- I don't care if all my friends add this junk, but I should be able to opt out of the messages with the news feed sliders.