There could be a common merge gateway, or common account merge protocol, so you can merge all your information between multiple accounts with ease.
Examples of this technology’s capabilities would be:
Merge and on-going synchronization of contacts, e-mails, and calendars between multiple computer applications, cloud providers, and ISPs
i.e. Microsoft Outlook, Gmail, Yahoo! Mail, Hotmail, MSN, Live Mail
Selectively merge calendars, tasks, and other types of information from Outlook / other mail applications with Cloud providers / e-mail providers web-based applications