Have you tried using Compassion Pit? Made by the same guy who made Awesomeness Reminders, mentioned by another commenter. Basically the same concept, just web-o

Have you tried using Compassion Pit? Made by the same guy who made Awesomeness Reminders, mentioned by another commenter. Basically the same concept, just web-only. Could be a cheaper start for gathering a user base and gauging long-term interest.