Whats the deal with #whatever on twitter?

[Kelvin Waterson]

I don't understand the significance of the # sign. Is this something to do with groups, or channels?

[chachafance]

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.