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If Thunderbird and Nintendogs had a love child, this would be it. PostPet is a graphical email program where emails are received and delivered by a virtual pet that you take care of. If your friend also has PostPet, their pet will come to your virtual house and deliver the email, and then interact with your pet. Forget to take care of your pet, and it'll get angry, and may even refuse to deliver your emails!



Website (Japanese): http://www.postpet.so-net.ne.jp/
Website (English, discontinued): http://www.postpet.so-net.ne.jp/en/
Design article: http://www.lisahazen.com/samples/postpet.html