MoodScope is a website for measuring, tracking and sharing your mood. A daily email prompts the user to visit the site, where mood is measured using an online card game. Users can choose to share their scores with family and friends, with the idea that sharing changes in our mood with friends can help improve it. Users can also chart their scores over time, looking for particular stressors of anxiety, depression or happiness.
Alexandra Carmichael, director of the Quantified Self, has an interesting blog post on her personal experiences tracking mood with Moodscope.