2. How can I see friends' names when it says "Popular with 5 friends"?
You can't. We want to let you know what's popular in your crowd, but we also want to respect people's privacy — SeenThis? shows recommendations in ways that are not individually identifiable. If your friends want to call attention to something specifically, they can always share it with you, or post it to their Facebook profile with the "Share It" button. For more information on our privacy features, please see our Privacy FAQ and Policy.
Moochspot is pretty cool example. It even works without having to add Moochspot as an application on FB. Question - doesn't it violate the FB Storable Information rules that you cannot store relations between IDs? That is, I add my FB friends to my piggybank so the piggybank is essentially storing that friend relationship.