This article first appeared in the St. Louis Beacon, Nov. 1, 2010 -Our Editor Margaret Freivogel and Public Insight Network Analyst Linda Lockhart were at the Online News Association's annual conference, in Washington, D.C., at the end of last week. In addition to the ONA's conference website , I was able to follow the proceedings on Twitter.
Twitter doesn't inherently include a way to have a group conversation. You can reply to people by using their username preceded by a "@" symbol, but to tag more than one or two people is inefficient given Twitter's 140-character limit.
However, when a lot of people at an event are using Twitter, often a hashtag will emerge. People will start appending this code to their messages, allowing discussion about the event to flow among attendees and otherwise interested people.
A hashtag is a short abbreviation or word, preceded by the pound sign, or hash. The hashtag for the Online News Association's conference was #ONA10. Hashtags can pop up around events -- they became popular in 2007 when people tweeted about wildfires in California using the hashtag #sandiegofire. They can be used to identify groups or teams, as in #stlcards. They also can mark tweets as part of a game or joke, as in a recent spate of humorous tweets featuring the tag #greengrocerrock along with band names made of vegetable puns.
So why does this matter? Consider the San Diego fire. Hundreds or thousands of people were tweeting about the fire, but how could you search for it? The tweet might include the words San Diego or it might not. If it does, the tweet might be about the fire or it might not. Likewise with the word fire (it might be about a fire someplace other than San Diego). Given the nature of the medium, you might construct a tweet about the San Diego fire that doesn't include the words San Diego or fire.
The hashtag solves the problem. Including the tag #sandiegofire in the tweet provides immediate context to the reader, and a consistent way for people seeking the information to find it. Someone might say "#sandiegofire smoke very thick, visibility 1/4 mile at 805 & 94," while another tweet could read "Does anyone have info on predictions for #sandiegofire progress, weather conditions?" and finally "On vacation, but just heard from neighbors our house is safe! #sandiegofire."
A search for the tag would return all three tweets for someone seeking information about the fire. If there were no tag, the tweets might have been written in a way that would make finding them all in one search very difficult.
Twitter makes it easy to follow hashtags. If you have a Twitter account, you can click on any hashtag on your homepage there, and you'll see a list of tweets using the tag. You can also go to search.twitter.com and type in a hashtag to see who's been using it.