What is the difference between A Direct Message And A Reply?
Direct Message: (DM) is a private conversation you have with only individuals who are following you. To send a DM all you need to do start your Tweet with the letter “@” followed by the users twitter name and then type your message. If you attempt to send a DM to a person who is not following you Twitter will let you know there is a problem with an error message. This is a wonderful limitation because you will only receive a DM from someone who you are following.
Replies: If you want to direct your comments to one specific person but would like everyone else to see it then use the “Reply” function. You address the person by using their Twitter user name preceded by the “@” symbol.