Contact synchronization occurs every four hours and is limited to 10,000 contacts. Once this number is reached, data synchronization of new contacts will stop and the BlackBerry smartphone user will get the following message:
You have reached the maximum number of contacts allowed by your <emailaddress> account. The BlackBerry Internet Service will continue to synchronize the existing contacts for <emailaddress> on your BlackBerry device to your <emailaddress> account. You can continue to add contacts for <emailaddress> to your BlackBerry device but the BlackBerry Internet Service will not synchronize these new contacts with your <emailaddress> account.