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Page history last edited by Chris Messina 13 years, 11 months ago

Hashtags Introduction 

Hashtags are a community-driven convention for adding additional context and metadata to your tweets. They're like tags on Flickr, only added inline to your post. You create a hashtag simply by prefixing a word with a hash symbol: #hashtag.

Hashtags were developed as a means to create "groupings" on Twitter, without having to change the basic service. The hash symbol is a convention borrowed primarily from IRC channels, and later from Jaiku's channels

hashtags.org provides real-time tracking of Twitter hashtags. Opt-in by following @hashtags to have your hashtags tracked.  Similarly, Twemes offers real-time tracking without the necessity of following a specific Twitter account.  Also, with their purchase of Summize, Twitter itself now offers some support of hashtags at their search engine: http://search.twitter.com. Other services such as TweetChatTweetGrid, and Twitterfall are also popular for following hashtags in real-time.


How To Use Hashtags

Start using hashtags in your tweets, preceding key words. It can be helpful to do a little research first, to find out if the subject you're tweeting already has an established hashtag. Also, check Suggestions and Tips and Example Uses below for ettiquette and general usage.

Finally, track other tweets on the subjects you're interested in (ie: those containing the appropriate hashtags) by browsing/searching at Hashtags.orgTwitterGroups, TweetChat, TweetGrid, Twitterfall, etc. You can set it up with RSS feeds as well.


Use of hashtags 

Hashtags were popularized during the San Diego forest fires in 2007 when Nate Ritter used the hashtag "#sandiegofire" to identify his updates related to the disaster. 


Chris Messina wrote up this use in his post on Twitter hashtags for emergency coordination and disaster relief

Subsequent uses have emerged, especially alongside Twitter's track feature and the development of hashtags.org, which shows useful graphs of popularity and recency of hashtags. Another useful tool was the Terraminds twitter search engine that allowed for searching for arbitrary hashtags (search for #hashtag), but is now shut down.


Suggestions and tips 

The use of hashtags is still an emergent phenomena, and as such, etiquette is negotiable, though some have already expressed their distaste for hashtags. 

Used sparingly and respectfully, hashtags can provide useful context and cues for recall, as well as increased utility for the track feature. Used excessively can cause annoyance, confusion or frustration, and may lead people to stop following you. It's best to use hashtags explicitly when they're going to add value, rather than on every word in an update. 

A good rule of thumb to follow is to focus on your update first, and only if it quantitatively adds value, to append one-three hashtags. There are no hard and fast rules, but Twitter should continue to be about answering the simple question: "What are you doing" rather than "What tags apply to what you're doing?"



When creating a hashtag for something that may consist of two or more words its a good idea to use the "CamelCase" format to maintain legibility. The idea is to join words with each words initial letter capitalized. For example if I wanted to create a hashtag  for south Africa, I would type out: #SouthAfrica instead of #southafrica


Example uses 

  • Events or conferences, e.g.: "Tara's presentation on communities was great! #barcampblock" 
  • Disasters: "#sandiegofire A shelter has opened up downtown for fire refugees." 
  • Memes: "My #themeword for 2008 is conduct." 
  • Context: "I can't believe anyone would design software like this! #microsoftoffice" 
  • Recall: "Buy some toilet paper. #todo"
  • Quote: "Great minds discuss ideas. Average minds discuss events. Small minds discuss people." ~Eleanor Roosevelt #quote

Further reading  

(In rough chronological order) 


Known issues  

  • The hash symbol has other uses, notably for denoting indices ("I'm #1!") or phone numbers ("Dude, what's your #?"). It's hard to avoid these kinds of collisions and they are simply something to consider modifying a common communication channel. 
  • Triple tags are not being parsed by some web services -e.g. #taxonomy:binomial=Alcedo_atthis is interpreted as being tagged simply "#taxonomy" by Summize and Twemes. Worse, HashTags simply renders the content as "#taxonomy", losing ":binomial=Alcedo_atthis" altogether. Twemes defend this on the grounds that triple tags are (were!) not covered in this spec, and claim a clash with colons as punctuation in casual conversation. The latter is bogus, as colons in conversation are generally followed by a space: as in this sentence. Also, plain-text sentences using a colon, followed by an equal sign, and preceded by a hash, and without spaces, #are:extremely=unlikely.
  • Spamming of hashtags - what can be done when a bot network of porn spammers insert into a hashtag?  (a weblog post talking about similar issue)


Hashtag definitions 

Hashtags may be defined (or their defintions found) using:


On Twitter:






Hashtag apps 

  • FollowFriday.es          Spanish Twitter Ranking based on #followfriday recommendations.
  • TweetChat                  Track hashtags in real-time
  • Tweet of the Year      Vote for the best Tweets of the year!
  • LazyTweet                 Ask questions from the twitter crowd
  • Tweetmapper            Use hashtags to map your location
  • Tweetag                    Aggregate tweets into topics and subtopics
  • Twuoted                   All the #quote's on twitter.
  • Twitter-Trends           Aggregate German hashtags
  • Hash-Dump               Register the hashtags you've created and get credit for them.
  • HashParty                  A twitter hashtag explorer that uses the Ident Engine to reveal the social graph profiles behind the tweets.
  • Twimonial                  Let Twitter users use #twimonial to write a testimonial about a Twitter user


Hashtags users  

Hashtags are admittedly an early-adopter feature, but have been picked up by a number of folks. If you see folks making regular use of hashtags, feel free to point them out here: 


Comments (13)

Anonymous said

at 2:57 pm on Jan 12, 2008

What's the difference between hashtags and track?

Chris Messina said

at 5:26 pm on Jan 12, 2008

Read this: http://factoryjoe.com/blog/2007/ 12/23/making-the-most-of-hashtags

Ontario Emperor said

at 8:31 pm on Jan 21, 2008

Regarding the list of references down toward the end of the page - would there be any objection if we added parenthetical statements after the author's name, containing a brief summary of the content of the link? (e.g. the Nate Ritter link could have the statement "(account of tweeting #sandiegofire information)"

Chris Messina said

at 4:03 pm on Aug 27, 2008


Hillary Hartley said

at 2:34 pm on Oct 15, 2008

weird spacing after i hit save. tried to edit them out, but they are back. ack.

jmb said

at 4:49 am on Jan 22, 2009

When you start following @hashtags, will it request your user timeline immediately and pick up hashtags in tweets made before following?

Julia Gilbert said

at 7:41 am on Feb 4, 2009

We created @tagref (and http://thebounder.co.uk/tagref/) because we were seeing lots of #hashtags that we didn’t understand, both in our regular contacts’ tweets and in Twitter search’s ‘Trending topics’.

If you try a simple search for the hashtag alone, it could potentially return thousands of tweets, most of which may not enlighten you as to what it actually means.

As far as I know, there is no other way to 'define' what a hashtag means? I guess you could search for the first ever mention of it, but it still might not help.

John Nastos said

at 9:49 am on Feb 6, 2009

some of you may be interesting in @tagalus (http://tagal.us), which lets you define hashtags. Similar to what @tagref was suggesting, but more involved

Alex Lim said

at 5:34 am on Jun 24, 2009

Twitter trending topics, search and related applicatins thrive on these hashtags, as they serve as noted keywords in the sea of tweets going through the microblogging platform. So determining the perfect hashtag is akin to creating the perfect title for a blog post.


John E. Bredehoft said

at 8:41 am on Sep 23, 2009

It took almost two years, but I finally did it. Under my old pseudonym, I had previously proposed (in January 2008) that parenthetical explanations be added to the ends of the "Further reading" entries. I've added a few of these, and hope that others will add more and (when necessary) improve the parenthetical summaries that I wrote. In addition, if there are any discussions regarding Twitter's formal adoption of hashtag support, perhaps they should be added to the "Further reading" list also.

Hi-Tech Bookkeeping Services said

at 2:14 am on Dec 18, 2009

Yeah It's Great to use # tag in Twitter because you can create your own group ............

C Scott Crider said

at 6:15 am on Mar 24, 2010

As smart phones, and access to Twitter reaches near-ubiquity, it may be beneficial for Twitter to work with the public sector to establish and promote certain hashtags for "official use only." For example, it may be advisable soon to set #911 as an "emergency tweet channel" that can be monitored by 911 operators, enabling victims and witnesses of crime and/or natural disasters to communicate silently if necessary, or when signal quality makes it difficult to get calls out.

John E. Bredehoft said

at 8:56 am on Jun 25, 2010

I don't know that I'd trust Twitter "to establish and promote certain hashtags for 'official use only.'" Twitter's official support of retweets pretty much went against what the public sector is doing with retweets, so I'm not sure that I'd want Twitter to be the keeper of official hashtags. However, if not Twitter, then who?

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