What Are Hashtags?

A hashtag is a single word preceded by the pound or hash symbol (‘#’). Using hashtags adds some context to your tweets. The best way to illustrate this is with some examples:

• I recently attended a party that it’s host had named ‘Bling Nite’. Several of us talking about this party on Twitter included the hashtag #BlingNite in our tweets. ANyone could then search for ‘#BlingNite’ to find all the conversations about this party. (It was a great party – Thank you, Jennifer!
• Many people are using the hashtag #swineflu when publishing breaking news about swine flu. By searching for that hashtag you can keep up with breaking news about it.

Just as we tag blog posts; just as we tag photos on Flickr, we use hashtags to say, “This is what this tweet is about” or mark specific words has being significant.

The idea was originally put forth by Chris Messina in this post. They were used extensively during the San Diego fires in 2007.

One really novel use of hashtags is my attendees at conferences. While the speaker or panel is underway the audience uses a specific hashtag to discuss the topic.

Anyone can create and use a hashtag.

In addition to making it easy to search for and follow a specific topic, hashtags off another novel use. THere is a sight named hashtags.org that tracks hashtag usage. If you follow @hashtags then your hashtag usage will be tracked too. Hashtags allow you to guage the popularity of a topic. For example, here is a graph displayed by hashtags.org displaying the use of the #swineflu hashtag:

In other words, hashtags not only help us find conversations about specific topics, they help us understand what people are talking about. This is kind of ‘meta search’, where we are less interested in the search results themselves that the data about the search results. An interesting concept and one that has yet to be fully explored.