(Fluff)Friends is a new Facebook app that lets users adopt a virtual pet to embed on their profile. It incorporates a virtual currency system, too -- (Fluff)Friends owners earn "munny" by petting or feeding the pets of their friends, or by filling out marketing surveys. So it's a gain for the surveys, but it also encourages social play, since you don't earn any munny for taking care of your own pet.

Munny can buy food and gifts for your pet or others', and taking good care of your pet raises its speed, which in turn raises the probability that it can win "races" against other pets for munny prizes. The more friends who accept your invitation to adopt a (Fluff)Friend, the more options you have for your pet -- you can customize them with backgrounds, mini-pets and other accouterments.