With over 70% of social users regularly using hashtags, it is know seen as a vital tool for social networking and it is important to understand why, when and how to use the #.
Basically, the hashtag is used to either direct readers to related content threads for a particular subject, or to attract others who have an interest in that subject to interact with your post.
The # (also known as gate or pound) was first used on the web in 1988 when it was used on IRC (Internet Relay Chat) which was used for group messaging.
The hashtag as we know it now was first used on Twitter in 2007 by Chris Messina (see below)
Bad @ Being Bad 