#hashtag.
First off what is a hashtag? Well accroding to Wikipedia…
“A hashtag is a word or a phrase prefixed with the symbol #
,a form of metadata tag. Short messages on microblogging social networking services such as Twitter, Tout, identi.ca, Tumblr, Instagram, or Google+ may be tagged by including one or more with multiple words concatenated, e.g.:#Wikipedia is an #encyclopedia. Hashtags provide a means of grouping such messages, since one can search for the hashtag and get the set of messages that contain it.”
The best part about a hashtag is that anyone can create one! Its as simple as placing the # symobl infront of the word or phrase you want to make a hashtag – and voila! You have created a hashtag.
I’m not an expert on creating hashtags though, so for some advice on how to make a use hashtags check out this article:
http://www.hashtags.org/platforms/twitter/why-use-hashtags-guide-to-the-micro-blogging-universe/
and you soon will become a hashtag expert!