While PEIR uses a piece of custom software that runs in the background, YFD requires that users actively enter data via Twitter. Twitter is a microblogging service that asks a very simple question: what are you doing right now? People can post, or more appropriately, tweet, what they are doing via desktop applications, email, instant messaging, and most importantly (as far as YFD is concerned), SMS, which means people can tweet with their mobile phones.
YFD uses Twitter's ubiquity so that people can tweet personal data from anywhere they can send SMS messages. Users can currently track eating habits, weight, sleep, mood, and when they go to the bathroom by simply posting tweets in a specific format. Like PEIR, YFD shows users that it is the little things that can have a profound effect on our way of life. During the design process, again, we keep the user in mind. What will keep users motivated to manually enter data on a regular basis? How can we make data collection as painless as possible? What should we communicate to the user once the data has been logged? To this end, I start at the beginning with data collection.