SmileTracker is a system designed to capture naturally occurring instances of positive emotion during the course of normal interaction with a computer. A facial expression recognition algorithm is applied to images captured with the user's webcam. When the user smiles, both a photo and a screenshot are recorded and saved to the user's profile for later review. Based on positive psychology research, we hypothesize that the act of reviewing content that led to smiles will improve positive affect, and consequently, overall wellbeing.