The Full form of DM is Direct Message. DM is a social media term that allows private messages between users of a social network. Direct Message (DM) is a messaging function in many social media applications and only visible to the sender and recipient(s). The term is popular on social media networks like Facebook, Whatsapp, Snapchat, Twitter and Instagram. On the Twitter site (a free social messaging tool), DM is short for direct message and it is used to send a private tweet (Twitter update) to a person you are following. You can view DMs from the Messages tab of your Twitter profile. You can also choose to receive email notification of new messages.