Outlook Web App and Outlook.com support attach and share of files directly from OneDrive for Business and OneDrive, great convenience.

Attach and Share Files in Outlook Directly From OneDrive (Business and Consumer)

Updates to OneDrive service, web app and desktop clients will make it possible to upload 10GB files, share from PC and upload folders.

OneDrive Updates: 10GB Files, Dropbox-like Sharing, More