Twitter Hashtags

I used to be asked simple questions like what is the fax number for the Canadian Consulate in Zimbabwe. This is a question that any librarian would be able to find in 1 minute. Go to the topical table of contents for the Canadian Almanac and Directory – Find that Canadian Diplomatic and Consular Representatives Abroad starts on p. 882, flip to page 888 – Fax number is 263-425-2186. It almost takes as long to write the question as it does to find the answer.

These days I am asked for difficult things like what hashtag should I use for this tweet.

I do not know of a concept based hashtag dictionary. An authoritative source that has the best tag to use to express a concept isn’t jumping out from my browser searches. Hashtags are a critical element for sharing the message with the right potential audience that your twitter post is aimed at.

There are some methods for discerning tags:

None of these will immediately identify if you should use [or search] #YEGRE #REYEG #RealEstateEdmonton or some other hashtag choice if you are looking for tweets about Edmonton area real estate. My real estate agent contacts use #YEGRE in case you are wondering.

How do you decide what hashtag to use or search?


  1. For using hashtags, I usually check an event or organization website to see if one has been designated. Failing that, I do as you have and try different searches at Sometimes they are not obvious, however.

    For searching, even if a designated hashtag has been put in place, usage may vary and other tags may need to be searched to pull up all significant tweets.

    Originally there was a website where all hashtags were “registered”, but it died an untimely death, I suspect due to the volume. It is a challenge because people make up tags on the fly to express themselves in a clever way, not actually intending for them to be used beyond that one tweet. #itsapain

  2. I generally don’t use hashtags since, as you say, there isn’t a well known set, and people aren’t consistent about using them, so some tweets will get missed. Instead, I use lists of those microbloggers who post on certain themes, and if occasionally there are off-topic tweets, I figure it’s better than missing the tweets that didn’t get the hashtag.

    That said, your list of sources of hashtags in use is a good one – thanks!

  3. I like Connie’s initial approach, in that an organization or event might well set up an accepted hashtag or tags in advance, and it’s best to start with those.

    Hashtags are a folksonomy, not a taxonomy. They are used based on the social, professional, and, in some cases, personal knowledge management context of the tweets concerned. By definition it isn’t something you can look up in a directory. Some of the resources you point to address hashtags for all of twitter, which with millions of tweets a day is not likely to point your legal professional in the right direction.

    So, I would ask your questioner, what are you tweeting about? Who else tweets about that subject? What hashtags, if any, have those people used lately? What hashtags does the questioner follow? What are some common hashtags associated with those topics, organizations, and people, that others have used over an extensive period of time?

    For instance, my areas of interest include knowledge management and Enterprise 2.0. Some long-term tags used in that area include #km, #kmers, and #e20. An interesting one lately has been #lawfarm. I’m also a member and participant with the International Legal Technology Association–the primary tag related to that important organization is #ilta (although ILTA recently recommended that with the increasing volume of #ilta tweets, peer groups use more specific tags such as #iltakm; a search of #ilta would suffice to find those other more specific tweets).

  4. Catherine Deane

    I try to use the kinds of hashtags I would use if I were looking things up, but I am always open to change if I notice other people doing something different. Eg. I mostly tweet about legal research or legal news so I do #legalnews #lawnews #legalresearch #lawresearch but that takes up a lot of room so then I don’t have as much room for the actual tweet.

  5. Peter Rawsthorne

    Great post. Discussing a very important topic. Yes, #hashtags are often associated with events or conferences and are often determined by the organizers. Hashtags are also an important part of a Community of Practice and often determined by and promoted via the folksonomy approach. It may also be a good idea to not limit your use of hashtags or tags to just twitter. I have worked with a number of communities of practice where we agreed to a common set of hashtags / tags and “attached” these to our blog posts, delicious tagging, forum discussions, slideshare presentations, youtube videos, etc… anything we “touch” / create on the web would get tagged… Therefore, when we search the web for the common tag we get resources from multiple sources all related to the same subject.

  6. Daniele Mazzini


    I just wanted to add a new resource to the list of useful tools about hashtags:

    The focus of this website (which I just published yesterday) is on the relationships between hashtags, but in the future I’d like to add some new features. Comments are welcome!