(Thanks to Don Yarman for suggesting this topic–I’m always on the lookout for new fodder.  Send your ideas to meanlaura@oplin.org.)

I have to assume that, by now, your library has finally jumped on the Twitter wagon.  (See here for additional info about Twitter for libraries.)  If your library is doing Twitter correctly, then you are courteously following (most of) your followers back.  (And if it’s not, you should be and I think I’ll chat a bit about that in a future Mean Laura post.)  You may have noticed some followers using words in their tweets preceeded by the pound (#) sign.  These are called hashtags.

Why use a hashtag?

Hashtags are used as an easy way to designate certain topics when using the Twitter search.  For example, a couple of weeks ago, I attended the Computers in Library conference in Washington D.C.  The official hashtag for the conference was #cil2009.  If you use(d) Twitter search with that hashtag, you would be able to get a fascinating real-time picture of what people were saying about the various sessions, and even conversations being held asynchronously via Twitter.

Do they have any effect?

The past several days, we’ve seen the true power of the hashtag with the AmazonFAIL fiasco.  Customers have found all kinds of ways to use social media to demonstrate their disapproval of Amazon.com’s move to make all LBGT literature “adult.”  (Read the last link to see the gory details.)  But on Twitter, the #amazonFAIL hashtag not only identified people’s contributions to this large-scale conversation, but as of this blog post, the topic is actually the most talked-about on Twitter.  Clearly, people are very unhappy with Amazon.com and they are not only making it known on an unprecedented scale, but they are doing so at an incredible speed.

What does this mean to me, Laura?

1. If  your library tweets on certain topics regularly, ,it may be helpful to use a hashtag, such as #bookdiscussion.  Note, however, that these are called hashTAGS for a reason–just like regular keyword tagging, there is no authoratative source for taxonomy.  Just make up a hashtag and use it consistently.
2. As the Shifted Librarian, Jenny Levine, found out, hashtags seem to have a limited lifespan in Twitter search.  Read her blog post for how she gets around this.
3. Certain events and happenings have “official” hashtags, such as the #cil2009 and #amazonFAIL tags, above.  If you’re attending a conference, find out what the official hashtag is before you start tweeting.  Sometimes people don’t do this, and you’ll see variations on the tag, rather than one consistent tag.  As you might guess, this is less than ideal.
4. On the other hand, if you go to a conference and the conference folks haven’t set one, be the first to make it up and promote it.  People will often use what they see first.
5. Hashtags are primarily intended for Twitter, but you will also often see them in action on blogs.  If you search Technorati, for example, for “cil2009″ (no hash/pound sign), you’ll get a ton of hits.