What the “hash” is that?

Ever wonder what all the symbols are in all those tweets?

Twitter uses a few different symbols to achieve certain results for its users. Here’s a quick guide to these common symbols, but a simple way to remember is this: @ refers to Twitter accounts and # refers to topics.

The Pound or Hash Symbol ( # )

The pound or hash symbol is used to create a hashtag. This symbol is used to tag relevent keywords within a tweet. Doing so creates a hyperlink to other tweets using that same “hashtagged” keyword, enabling you to view a conversation stream (tweets from many people, sometimes coordinated, oftentimes not) based on that hashtag. This is commonly done around common interests, large events or with popular topics in the news.

Examples of hashtags: #BigData, #Bruins, #Obama

Examples of using hashtags:

  • Share information, or create a conversation related to an event. EX: #EMCworld
  • Host an impromptu virtual gathering, or communicate with an informal audience. EX: #Nerdherd
  • Add a smart alecky comment to a tweet. These are often not common across users. EX: #KeithIsOnFireToday
  • Indicate displeasure. EX: #FAIL
  • Social plugins use hashtags to integrate their services. For example, Selective Tweets can post your tweets to Facebook using #fb. LinkedIn allows cross-posting of tweets using #in or #li. Hello Bar is a web site or blog plugin that uses #hellobar to trigger cross-posting of tweets. 
  • More info from Twitter.com

The New Yorker covers hashtags (with some humor) in this June 2010 article.

Lastly, it’s okay to add punctuation or apostrophes after hashtags if gramatically necessary.


The “At” Symbol ( @  )
The “at” symbol is used to auto-link to a Twitter user (@kemipa), either in an @reply or an @mention.

Examples of why one would link to another Twitter user:

  • Reply or respond to a tweet, known as an @reply. A reply is any update posted by clicking the “Reply” button on another Tweet. It will appear in the home stream of the user and within his/her Mentions screen.
  • Send a public mention, known as an @mention. The @username can be place anywhere in the tweet.
  • More info from Twitter.com


The dot Symbol ( . )

The dot symbol is used to override Twitter’s automatic filtering of @replies. In the early days of Twitter, all @replies appeared in the public timeline. Now they appear only to the users/followers involved. The dot-at (.@username) approach forces all @replies into the public timeline. Use judiciously in instances where you think all of your followers will benefit from this conversation.

Instead of beginning a reply tweet with @username, start the tweet with .@username. The @username receiving the tweet will still know that you’re sending a reply, and everyone following you will see it too.


The $ Symbol

The $ symbol is used to denote the stock ticker symbol for a company within the context of a related topic. You’ll see $EMC, $VMV, among others. Unlike hashtags, the $ symbol does not auto-link the keyword, nor is officially supported by Twitter.


Other Symbols
You might also see hearts (♥) or music notes (♫) or arrow symbols (») in tweets. These are nonstandard characters, but can be used with a bit of keyboard trickery. Here’s how.


Adapted from a blog post I wrote on EMC|ONE, EMC’s employee community.

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