Yes, it does. While there is no dedicated Bcc: button in the Addresses window, you can still add contacts to the Bcc: field in an email easily.
Address Messages Comfortably in Mac OS X Mail
To address messages dragging and dropping names in Mac OS X Mail:
- Start with a new message in Mac OS X Mail.
- Click the Address toolbar icon.
- Alternatively, select Window | Address Panel from the menu.
- Click in the desired address field in the message composition window (To:, Cc: or Bcc:).
- Double-click on the desired email address or contact in the Addresses window.
- Close the Addresses window.

