For those of you who have been on twitter for a while, you most likely have noticed and know what a hashtag is. For those of you new to twitter, you may be saying, good god not another twitter term I need to know about.

Actually, hashtags can be a great tool and serve many useful purposes. Not the least of which is the fact hashtags are wonderful if you are following a particular conversation on twitter. We will discuss more on that later in this post.

Hashtags serve a number of functions

• They get a topic noticed by those on twitter
• Help get you noticed on twitter too if you are the one who is pushing the hashtag
• Hashtags are picked up by the search engines and do great there too
• They are a powerful community builder on twitter
• You can use them to promote and tease tweeters about an event or product

Some of the points mentioned are fairly self-explantory. I do want to touch on a couple of them in more detail below.

Promoting an event or product

This last weekend, Clay (the other G in G2WebMedia) and I attended WordCamp Dallas. The hashtag for this event was #wcdfw09. Not only could those attending the event get updates by following the hashtag. Those not there could do the same thing. The best way to do this is to use twitter search and type in the hashtag. As you can see from the image below, the search results were many.

If you promote your hashtag correctly on twitter, people can use twitter search like I did above to keep up on what is happening at an event or even on a product launch.

Here is how you can use your hashtag to promote your own even right in your tweets.

Simply put the hashtag in your tweet and it will show up in your stream and in the search results as indicated above. Using them is a great way to promote anything you are following or that you want people to notice and keep up on.

As you can see from the example for #wcdfw09, a community was built around the hashtag too. Those attending the event used it to keep up on what was going on. And we were able to keep up on the conversation centered around the event. Which, in and of itself is a great use and benefit of the hashtag.

Following a conversation

The best example of this is a twitter even and/or conversation which takes place weekely, #blogchat. This is an open conversation on twitter where @MacCollier invites those on twitter to engage in a conversation. If you are curious how this works and what a great tool it is, take a look at the transcript from this weeks #blogchat.

Picking a Hashtag

When you are first looking at picking a hashtag, you need to look at what you are wanting to talk about. The topic; is it an event or a product. It could even be an regular ongoing conversation taking place on twitter, like #blogchat mentioned above.

The main thing to remember is to try to make your hashtag fit the product or event and keep it short. The example above #milofest is a great example. This hashtag fits an event and is short and easy to remember. And that is key. Don’t make people think when they go to type in your hashtag.

You want your hashtag to communicate to those on twitter what it is you are talking about. Be consistent too. Once you decide on your hashtag, stick with it. Don’t change it or alter it in anyway. People are going to use tools like twitter search to follow hashtags. And if you change it, you are going to loose your intended audience.

Your Homework

If you see a hashtag being used on twitter, use the search function in your twitter client to follow it. Or use twitter search to do the same thing. You not only will get some great information. You may also find some new people on twitter you might want to follow.

And if you are promoting an event or a product, try using a hashtag to get it noticed on twitter. It really does work.