Hash tags (also spelled hashtags), or Twitter keywords with the sign # in front of them, are a user-generated convention for asigning a topic or context to tweets. A hash tag looks like this: #Chicago.
These indicators of topic act as both hooks and groups:
So let’s say that you see this in your Twitter stream:
“I just downloaded the #hashable application for #iphone”
You may want to click #hashable to find out what it is and to see what others are saying about it, or you may want to see what other iphone news people are sharing. The hash tag just hooked you in.
But topics designated by hash tags can vary from products (#iphone) to technology (#android) to events (#atmidwest) and actual Twitter chats (see #blogchat). Particularly in the case of an event or when a discussion suing a particular Twitter hash tag is organized to happen a certain day and time, the hash tag functions as a virtual chat room.
When and How?
You can use a hash tag within the tweet or at the end of a tweet. For example: “I hope the #Chicago #Blackhawks win again,” uses the hash tags inside the message. “Let’s go Blackhawks! #Chicago #Hawks,” places the tags outside the main message of the tweet.
Always use a hash tag in these situations:
In the case of a chat, you may want to only focus on that hash tag for the duration of the chat. There are websites that facilitate this, such as tweetchat.com and tweetgrid.com. Go to the website, enter the hash tag, and you will be able to focus on that conversation exclusively.
When setting up a new hash tag:
A more unusual way to use hash tags is for emphasis, or almost as a “footnote” to a tweet. This doesn’t indicate a topic or a chat, but is just a reflection of how pervasive hash tags have become in online communication.
“I’ve been scrubbing and cleaning all day! #needahousekeeper”
Use them much but don’t overuse them
Using too many hash tags in one tweet is spammy, ugly and useless. So don’t do it. I recommend one or two hash tags per tweet, maybe less but no more. Tweet with grace.