A Windows Phone trick that you (probably) didnt knew about.
Source | WMPowerUser
Did you know you can send private messages to your Twitter friends via Direct Messaging by using the built-in People Hub?
All you have to do is put a capital "D" in front of the twitter name you want to send a message to. This way it will convert your tweet into a direct message.
This is a very useful tip for those who wants to share private messages with friends without downloading a Twitter App on their Windows Phone.