What is it with Twitter and # (hashtags)?

[freya]

I do not use twitter but from reading alot of articles about celebrities which always links them to their activity on twitter I've never understood why people use hashtags in their tweets?
Here is an example from an article about Rylan Clark and Spencer Pratt from Big Brother
"Missing you also! Hope your rocking the roof on the X Factor tour! #dropmeout."
Is there a reason for it?

[LoveDies]

i Think the hash tags turn into a link to another page


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[Yanni Depp]

yes

[yacoffee]

The hashtag will be on a particular discussion topic so if you want to follow what everyone said on that hashtag topic you can just type it in and follow it. It's a way to organize the millions of tweets and make sense of them.