What Does DM Mean on Twitter?by Robert Schrader
A social media service, Twitter operates much with the same goal as sites like Facebook and MySpace -- to keep you in contact with a large network of family, friends and professional associates. Twitter's mechanism, however, is more streamlined: communicate using short messages known as "tweets," which you send to your whole network, or by sending a direct message, also known as a "DM."
Tweets vs. Direct Messages
The basis of Twitter is simple: each user follows certain other users, and certain other users -- who may or may not be among those he or she follows -- follow him or her. When a user sends out short messages known as "tweets," every user who follows that user can see the content of the tweet. With a direct message, on the other hand, only the specific user to whom the message is addressed can view it.
One common characteristic of tweets and direct messages is both must adhere to Twitter's established character limit. As is the case with a tweet you send to your base of Twitter followers, direct messages you send to a specific user must be less than 140 characters in length. Additionally, you can embed links to images and auxiliary websites within your direct message to refer the reader to additional content or information.
Just as your tweets are visible only to those users who've followed you, it's only possible to send direct messages to the same pool of users. If you click the profile of someone who follows you, you'll notice the option to send that user a direct message appears under his or her name. If, on the other hand, you navigate to the profile of someone who doesn't follow your tweets -- even if you follow this person -- this option won't appear.
Another circumstance under which you'll find yourself unable to direct message another user is if that user has blocked you. For a variety of reasons, a user who has previously followed your tweets may choose to block you, which removes your tweets from his or her Twitter feed and prevents you from communicating via DM. Additionally, you won't be able to view that user's profile when you're logged into your account.