(TERRE HAUTE) - You see them on Twitter, Instagram, and soon to be Facebook.
Michael Clouse of WTHI reports that it's the number or pound sign, which is now known by a different name.
"Hashtags are kind of like the subject line of an email, if you will," said Alex Mullins. "They don't have to be first but they tell you what the tweet's about."
Alex is a senior Computer Science major at Rose Hulman Institute of Technology. He's also an avid hashtag user.
"If I'm promoting an event on campus, certainly I'll use hashtags, or even if we're just talking about something we're doing, you know, just kind of keeps thing together."
By adding this symbol, you automatically associate your message with hundreds, thousands, or even millions of others from around the world.
Basically, it assigns it to a group.
Many use it to describe an emotion, but it's evolving.
It's become popular among businesses or television shows, asking you add a particular tag after your post.
"That kind of lets them focus their responses so everybody with a hashtag," said Mullins. "You know, ESPN 2013 or whatever it may be; it provides them a way to respond, kind of groups the conversation all together."
However, it's not just for entertainment. It can also be educational.
For example, during major national events, information can be gathered quickly just by a simple search.
"After Hurricane Sandy, it was hashtag Sandy or something to that effect," said Mullins, "so everything you wanted to know about, sometimes before even more traditional outlets even came out with the story was on Twitter."
Proving that something often used to describe a feeling, can now be used for much more.
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