The ability to import data into Office 365 in a quick and easy manner has been a known constraint of Office 365, and a solution for this issue has emerged as a key request from customers. The engineering team has been working on a solution that will allow quicker imports of data into Exchange Online Archive Mailboxes. You will now be able to import Exchange Online data through PST files into the service without using third party tools. Drive Shipping and Network Based Ingestion options will use Azure-based services to import data. Over time we will be extending this to other data types across Office 365.
From our O365 Roadmap: http://roadmap.office.com/en-us
More about it from the Azure import/export transfer service here: http://azure.microsoft.com/en-us/documentation/articles/storage-import-export-service/