• “@” (e.g., @RyanMadanickMD): This is a user’s Twitter handle.  Think of it as their username.  The “@” symbol simply defines to the Twitter server that you are speaking directly to or about a particular user.  This has 2 primary uses: a reply or a mention.
  • Reply (aka an @reply): When you reply to a particular user by clicking the Reply button under the tweet, the user’s @username will automatically appear at the beginning of your tweet, and you can then respond, as @otorhinolarydoc would have done in reply to @pbjpaulito in the conversation below.  When you reply to someone, your tweet will then appear in the user’s Mentions section on the Connect page of Twitter.  Be aware, though, that the @username does indeed count against the 140 characters allowed by Twitter.
  • Mention: If you are not replying to a particular user’s tweet, but you’d like to say something to or about him/her, you “mention” them by first typing the “@” symbol followed by his/her username.  For example, I might tweet: “Thank you @DoctorNatasha for helping with this blog!” Similar to an @reply, a mention will also appear in a user’s Mentions section.  You can mention more than one person, but just as above, each user’s name counts against the 140 character limit.

   

• “#”: In Twitter-speak, this is known as a hashtag.  Think of it as a keyword or topic of the tweet. It can be used in the middle of the tweet, like this: or tagged on to the tweet, often at the end, to delineate a particular category, such as #meded for medical education, or a topic, such as a medical conference like Digestive Disease Week (#DDW12).  Several years ago, a group of Twitter users established the Healthcare Hashtag Project to help standardize the use of hashtags for healthcare.  This site is quite useful if you’d like to see if a particular hashtag is already in use in the medical Twittersphere.

• RT: This means “Retweet”, which simply indicates the reposting of another user’s tweet.  On their website, Twitter makes it easy to retweet a post by simply clicking on the “Retweet” link that appears under the original tweet when you hover over it. However, occasionally you will actually see “RT” appear in the tweet, often followed by an @username.  This isn’t officially recognized as a Retweet by Twitter, but often is done to allow you to add something to the original tweet, like this:In this tweet, the user (@rlbates) retweeted (“RT”) the original tweet by @DrJudyStone (who has mentioned @murzee), and added a small comment at the beginning of the tweet (“+1”).  You might now be wondering what “+1” means.  This is a lexicon that many Twitter users employ to indicate their agreement with the particular tweet (some people use other numbers too, to indicate even greater agreement!).

• MT: This means “modified tweet”. Usually Twitter users employ “MT” to indicate that they are retweeting someone’s post, but in order to fit their own comment into the 140 character limit, they needed to modify the tweet in some way. In these two tweets, @cmaconthehill essentially retweeted the original tweet by @TonyclementCPC, but modified it so that he could comment on @TonyclementCPC’s original tweet.

• Shortened links: Take a look back at the tweets above by @BetterHealthGov or @rlbates. At the end you will notice some short URLs (or web page addresses): “ow.ly/b41k2“, “ow.ly/b41lh“, and “vsb.li/MmXZGG“.  Don’t worry too much about the specifics of these, but you should know what they do.  If you click on one of these links in a tweet, they will take you to a pre-specified web page.  It just has shortened the web page’s address to a manner that will more easily fit into a tweet.  As an example, the first link (ow.ly/b41k2) takes you to a page with the following address: www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Crohn’s_and_colitis_dietary_considerations. The web page’s address takes up nearly 100 characters by itself!  There are many ways of creating these shortened links, but if you want to start including links in your tweets, Twitter itself will shorten links you enter into your own tweets.

Let me know if there are other semantics you’re having difficulty understanding!