The '@' symbol is commonly used in Twitter.
Being up-to-date with what's going on in the world makes all the difference with being a member of Twitter---one of the most popular social networking applications on the Web. Whether it be from your desktop computer or your mobile phone, Twitter is available right at your fingertips. Twitter posts can only handle 140 characters so acronyms and abbreviations help with sending messages quickly and efficiently.
@
The @ symbol in the beginning of a username followed by a message, sends the message or "tweet" to that person and is displayed on your timeline. You can reply to a tweet that is sent to you by clicking "Reply". People with private accounts cannot send replies to people that are not following them.
#
A hash tag or pound symbol (#) preceding a word categorizes it so people searching for that word can find it easily. For example, a popular trend #FF or #FollowFriday will include posts that are sent by people about people they recommend that you follow. By clicking on the #FF link, you can view real time posts about people you can follow. Hash tags can be anywhere in the post, as long as the pound symbol is right before the categorized word.
DM
A Direct Message or DM is a private message between you and another person that only the two of you can see. Long conversations are typically sent via direct message and can only be sent to people that are following each other. To send a direct message, type the letter "D" in front of their user name. The message will be sent directly to their Twitter inbox.
RT
RT stands for retweet and allows you to repost a message on your timeline. You may retweet the message to your followers if you feel the message is beneficial or informative. Common retweets are inspirational quotes, funny posts or an important event such as a birthday party that people are invited to attend. The letters RT are posted before the username of the person that originally posted the message.
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