Pet Society

Pet Society was a social Internet game developed by Playfish that could be played on Facebook. The
game ranked as one of the most popular Facebook applications. Players could design their pets by choosing genders, names, colors and altering appearances.

The user interacted with their pets through washing, brushing, petting and feeding. Players' pets could interact with each other within the "friend" network. Pets could visit the pets of their owner's friends and perform activities with these pets (washing, grooming, feeding, etc.) A pet could visit other pets as many times a day as it wished. The players received coins and Paw Points on their first visit of the day to each friend, but earn only Paw Points for subsequent visits. Participating in the Daily Lottery, visiting friends, winning awards, cleaning or playing with pets, winning hurdle races, or betting on the outcome of hurdle races also provided players with ways to earn coins. Visiting friends, buying items, and using the stadium earned players Paw Points.

http://en.wikipedia.org/wiki/Pet_Society