How can I send a tweet without taking my hands off the keyboard? If I'm typing a tweet in Mountain Lion's new Notification Center panel, is there a way to send the tweet without moving my hands to the trackpad to click the "send" button? I've tried return, enter, ⌘return, and other key combinations, but nothing obvious sends the message.
I didn't intend for this to become a self-answered question, but I think I found the answer:

⌘⇧D

The send mail shortcut works to send a Tweet also. Yay for discoverability.