As I mentioned in another post, Twitter and Google Plus aren’t the only social media sites using hashtags. Facebook, as I’m sure you have noticed, is incorporating them and, of course, Pinterest uses them as well.
And speaking of Pinterest, this word-nerd found a dream infographic about hashtags that most any writer would find interesting. In general, the sign is used to group off categories and highlight text.
I thought you might find this useful:
Image credit; Social Media Today, Kevin Basset and Pinterest
You can find a hashtag dictionary on twitter for all of your needs here.
It is interesting that the Oxford dictionary has only a simple definition of the word:
while the definition on Dictionary.com is more extensive;
[hash-tag] Show IPA Digital Technology .
noun1.(on social-networking Web sites) a word or phrase preceded by a hash mark (#),used within a message to identify a keyword or topic of interest and facilitate a searchfor it: The hashtag#sandiegofire was used to help coordinate anemergency response to the fire.2.a hash mark used in this way.
verb (used with object), verb (used without object), hash·tagged,
3.to add a hashtag to (a word, topic, or message): Someone on Twitterjust hashtagged the film festival.