What does the # sign mean on Twitter?

[JJRose]

Is there a Twitter tutorial online anywhere? Twitter's site wasn't very much help.

[leerendlem]

Got this from Wikianswers.com:

In Twitter, the number sign is called a "hashtag" and it's used as a way of grouping or categorizing tweets, as Twitter does not have that functionality included. So, for instance, during the presidential debates certain hashtags were set for everyone to use in their tweets when discussing the debates.

This allows you to go to Twitter Search, search for the hashtag and then follow all comments that include it. So in real time, you can follow the comments and respond to them, creating a conversation about a given topic.

Others use them to denote discussion of events, groups, TV shows, movies, themed discussions, world events, and more.