Have Microsoft purchased a hard drive factory recently? First SkyDrive Pro increases base storage to 25GB. Now Exchange Online mailboxes will have 50GB base storage. What a week! Plans that make use of Exchange Online Plan 1 use in-place archiving. This means the archive uses the base storage size of the mailbox. With the increase to 50GB, there's more space for the in-place archive, to keep your Inbox lean and mean.
Resource and Shared mailboxes increase from 5GB to 10GB. Kiosk users increase from 1GB to 2GB.
Increases will roll out to you from now to November.