What does the number sign mean?

[Hannah]

Whenever I see something on Twitter or even on Facebook, I notice the put a number sign before the saying. Here's an example on a picture: "Summer 2011 #MostDope". WHAT DOES THIS MEAN?

[M. L.]

They are called "Hashtags".

Twitter defines them as this:
The # symbol, called a hashtag, is used to mark keywords or topics in a Tweet. It was created organically by Twitter users as a way to categorize messages.

People use the hashtag symbol # before relevant keywords in their Tweet to categorize those Tweets to show more easily in Twitter Search.
- Clicking on a hashtagged word in any message shows you all other Tweets in that category.
- Hashtags can occur anywhere in the Tweet.
- Hashtagged words that become very popular are often Trending Topics.


Here's some pages that talk about them in great detail:
http://support.twitter.com/entries/49309...gs-symbols
http://www.techforluddites.com/2009/02/t...se-it.html