What is a hashtag?
There is really no point in being repetitive when you realize that there are very good information about something specific on the internet. One question that often arises on the Twitterverse is, what is a #hashtag?
Instead of trying to explain it to you, allow me to introduce some of the best definitions I have encountered while trying to figure it out for myself.
Mari Smith’s video about “What are they, and How to create one?” explains this in detail.
An Introduction to Twitter Hashtags
Tagging helps to organize and share our online information with others. By attaching one or more keywords to a Flickr photograph, for example, we group it together with others that have the same tag. Hashtags serve a similar purpose on Twitter, the social micro-blogging service. The aim is to bring some order to Twitter users’ published updates (“tweets”) and make it easier to follow a topic of interest. And you don’t necessarily have to be a Twitter user to get a benefit from hashtags. Read more from this excellent article on Wild Apricot Blog
Also, you can get and set definitions for #tags – A dictionary for (hash)tags on @tagalus website.