Definition: 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. (From Twitter.com) However the hashtag is more than what the definition explains. Hashtags are being used by companies to drive positive online communication and build brand recognition and loyalty. (http://socialmediatoday.com/tonyobregon/454 084/hashtag-marketing-rise)
Make your hashtag a trending topic. Trending Topics on twitter is when a hashtag becomes so popular and is used at a greater rate than other hashtags therefore it is put in the trending topic section on twitter, for a twitter users to view. Trending topics become popular through word of mouth or word of tweet, the more a hashtag is used the more popular it becomes.
Twitter has a specific algorithm that helps determine what will be a trending topic on twitter. Using the new algorithm twitter decides what is immediately popular and makes it a trending topic instead of using topic that have been popular for days or weeks in order to keep the trending topics the most up to date. Some TV shows even have twitter feeds going on while their show is running using a specific hashtag and certain tweets will be shown live on TV just by using the specific hashtag