What does that symbol mean?

[Imogen]

What does hashtag mean?? Xx

[Bam]

A hashtag is tag embedded in a message posted on the Twitter, consisting of a word within the message prefixed with a hash sign. Some symbols can be @, &, #, ect. u use them for like @(someones name after it) or u can use them so people will b informed about your lastest posts. Hope this helps!!

[Ny]

It's used on twitter regularly - it's to show a topic related to a particular subject.
See the link here for more info: http://www.techforluddites.com/2009/02/t...se-it.html


Outside of twitter, I actually have no idea, sorry.

[bjk1961]

until recently, # was called the "number sign" or the "pound sign".