The # (pound) symbol is called a hashtag and is used to mark keywords or topics in a tweet. It was created by Twitter users as a way to categorize messages and then adopted by Twitter and third-party tools. Because hashtags are hyperlinked on Twitter.com and are searchable, they serve as a form of findability. Precursors to Twitter hashtags: tags on Delicious and Flickr.
In the beginning, there weren’t enough people or tweets to worry about organization.
just setting up my twttr
— Jack Dorsey (@jack) March 21, 2006
But as Twitter took off in popularity, organization became a need.
how do you feel about using # (pound) for groups. As in #barcamp [msg]?
— Chris Messina™ (@chrismessina) August 23, 2007
Hashtags are like Twitter’s Swiss Army knife. They help organizers promote events and help participants share information with people who are present or just interested. They alert us to breaking news. They introduce levity and humor. They serve as a calling card for communities, some that chat at designated times each week or month and some that share information without regard for the clock.
In short, hashtags — this un-library-like, bottoms-up taxonomy — provide one form of structure for finding information in the firehose that is the Twitter livestream.
Key things to know about hashtags
- Capitalization doesn’t matter but spaces and punctuation/special characters do (don’t use either)
- Hashtags must have letters; all numbers will not work so append them to your letters
- Placement doesn’t matter
- Sometimes hashtags are intended as editorial commentary rather than as a method of findability
- Hashtags associated with breaking news or crises are often trending topics. For example, #welcometotheworld (for the new royal baby).
- Although hashtags were popularized on Twitter, they are now incorporated on many other digital networks such as Facebook and Instagram and Google+.
- Don’t over hash. Except when it makes sense to do so!
- Use simple, memorable hashtags for predictable events. Twitter has some examples.
- Pick a hashtag that works across platforms.