Apple launched its MobileMe service among an increasing number of holes and bugs.
Now users who want to protect thier iPhone data and contact information need to subscribe the service before the trial period expires.
MobileMe keeps a reference copy of the data stored in the iPhone, the data is been copied in cloud.
Users will have to keep track for when the trial period will be expiring. When the service is in full swing the data in the cloud is synchronized with the other devices owned by the user.
Apple has detailed records of credit cards so it can automatically charge for MobileMe service once the trial period is over. The service can also act as a backup in cases, if you happen to loose the iPhone data or the phone itself. There is a minor risk of loosing the data upon canceling the service. With the cancellation of MobileMe account, the data stored in cloud will also be deleted. So if any iPhone tries to sync then the MobileMe account will over-write the data with blank slate.
So if you want to continue with the MobileMe service and maintain your data, subscribe it from Apple now. The subscription price is not known yet. Apple will maintain your data only if you are a paid customer.