Your Shape: Fitness Evolved plans on keeping players motivated and encouraging interactivity is with the Your Shape Center, an online portal that not only provides feedback on your own progress but allows players to motivate each other through custom challenges. An example given was setting a certain number of calories users would need to burn over a predetermined amount of time. Then through the online portal, you could see which of your friends completed or failed the custom challenge in question.
It's a motivational tool Ubisoft hopes will keep users engaged over the long run. For a brief overview of Your Shape Center, stretch your clicking finger and head on past the break.