Participants will receive an individual session, Fitbit activity tracker, and access to a secret Facebook group with the addition of behavioral lessons, adaptive physical activity goals, tailored feedback summaries, and text messages.

Change in levels of physical activity, as measured by accelerometry (ActiGraph), from baseline to 6 and 12 months. Participants will wear an accelerometer on their wrist during a 7 day period.

Change in levels of physical activity, as measured by a modified version of the Godin Leisure Time Exercise Questionnaire, from baseline to 6 and 12 months. Participants report frequency of light, moderate and vigorous exercise, and average duration (minutes) for light, moderate and vigorous exercise bouts in a typical week. Scores for light, moderate and vigorous exercise are combined to compute total physical activity minutes/week.

Change in levels of light-intensity physical activity, as measured by accelerometry (ActiGraph), from baseline to 6 and 12 months. Participants will wear an accelerometer on their wrist during a 7 day period.

Change in levels of light-intensity physical activity, as measured by a modified version of the Godin Leisure Time Exercise Questionnaire, from baseline to 6 and 12 months. Participants report frequency of light, moderate and vigorous exercise, and average duration (minutes) for light, moderate and vigorous exercise bouts in a typical week. Scores for light-intensity physical activity are scored as minutes/week.

Change in levels of moderate-to-vigorous intensity physical activity, as measured by accelerometry (ActiGraph), from baseline to 6 and 12 months. Participants will wear an accelerometer on their wrist during a 7 day period.

Change in levels of moderate-to-vigorous intensity physical activity, as measured by a modified version of the Godin Leisure Time Exercise Questionnaire, from baseline to 6 and 12 months. Participants report frequency of light, moderate and vigorous exercise, and average duration (minutes) for light, moderate and vigorous exercise bouts in a typical week. Scores for moderate and vigorous exercise are combined to compute moderate-to-vigorous intensity minutes/week.

Change in steps per day, as measured by by accelerometry (ActiGraph), from baseline to 6 and 12 months. Participants will wear an accelerometer on their wrist during a 7 day period. Steps will be averaged over a minimum of 3 out of 7 days to calculate average daily step count.

Change in steps per day, as measured by by Fitbit, from baseline to 6 and 12 months. Participants will wear a Fitbit on their wrist during a 7 day period. Steps will be averaged over a minimum of 3 out of 7 days to calculate average daily step count.

Change in sedentary behavior, as measured by self-report Sedentary Behavior Questionnaire, from baseline to 6 and 12 months. Participants will be asked to indicate the number of hours they spend on a typical weekday and typical weekend day doing a variety of sedentary activities. Responses range from 1 (none) to 9 (6 or more hours). To obtain weekly estimates of sedentary behavior, weekday hours are multiplied by 5 and weekend hours are multiplied by 2 and summed for total hours/week.

Change in weight, as measured objectively with digital scales, from baseline to 6 and 12 months.

Change in health-related quality of life, as measured using the Medical Outcomes Study 36-Item Short Form (SF-36), from baseline to 3, 6, and 12 months. The SF-36 asks respondents to rate their health and abilities to do their usual tasks. The SF-36 uses a variety of questions and response options and includes 8 subscales (physical functioning, role limitations due to physical health, role limitations due to emotional health, energy/fatigue, emotional well-being, social functioning, pain, and general health). Responses are coded on a scale of 0 to 100 where 0 is the worst possible health and 100 is the most favorable health score. The coded responses will be summed to yield a Physical Component Summary (PCS) score and a Mental Component Summary (MCS) score.

Change in health-related quality of life, as measured using the Functional Assessment of Cancer Therapy-General (FACT-G) survey, from baseline to 3, 6, and 12 months. The FACT-G is a 27-item measure specific to cancer patients to provide insight into cancer specific factors in four dimensions (physical, social/family, emotional, functional well-being). Participants will respond to a list of statements that tend to impact people with cancer by indicating how much they are impacted on a scale of 0 (not at all) to 4 (very much). Scores for negatively worded statements are reversed so that higher scores indicate positive health. Scores from the four dimensions can be summed to create a total score. Total possible scores range from 0 to 108, with higher scores indicating increased well being.

Change in behavioral capability, as measured by self-report questionnaire, from baseline to 3, 6, and 12 months. Participants will be asked to rate how much they agree with six different statements. Responses range from 1 (strongly disagree) to 6 (strongly agree) and are averaged. Higher scores represent higher behavioral capability.

Change in self-efficacy for exercise, as measured by the Self-Efficacy and Exercise Habits Survey, from baseline to 3, 6, and 12 months. Responses for two subscales (Sticking to it, Making time for exercise) are averaged to yield a score from 1 to 5, with higher values representing higher self-efficacy for exercise.

Change in self-regulation, as measured using by self-report questionnaire, from baseline to 3, 6, and 12 months. Responses to two subscales (Exercise goal-setting, Exercise planning and scheduling), ranging from 1 (does not describe) to 5 (describes completely), are averaged to yield two subscales. Higher subscale scores represent higher self-regulation.

Change in social support for exercise, as measured by the Social Support for Exercise Survey, from baseline to 3, 6, and 12 months. Responses for three factors (Family participation, Friend participation, Friends on social networking sites participation), ranging from 1 to 5, are summed, with higher values representing higher social support for exercise.

Change in depressive symptoms, as measured by the Center for Epidemiological Studies Depression Scale (CES-D), from baseline to 3, 6, and 12 months. The CES-D is a self-report depression scale including 20 items that relate to depressive feelings and behaviors during the past week. Response options range from 0 (rarely or none of the time) to 3 (most or almost All the Time). Scores range from 0 to 60, with high scores indicating greater depressive symptoms.

Number of days physical activity tracked, as measured by Fitbit.

Number of days weighed, as measured by digital scale.