If you've spent any time on Twitter, you've probably seen a hashtag before. A "#" symbol sets off a hashtag. For instance, if you wrote a tweet about Google, it might look like this:

Here's a look at how to utilize Hashtags to organize information that you contribute and consume on Twitter. As the tweets pile up, the extra time you take to thoughtfully categorize your tweets with a hashtag will help the greater Twitter community (and you individually) make the most of the service.

The story behind Hashtags

Twitter (the company) didn't create hashtags. The Twitter community's early adopters came up with the idea to put a "#" in front of topics to add context to tweets. The tag would also help filter and sort them out for future readers.

According to a Twitter fan website, the hashtags achieved significant notoriety with Twitter users in 2007 during the San Diego fires, when users designated their tweets with "#sandiegofires."

The trend to use hashtags led to the community-driven site hashtags.org, where a semi-official index of Twitter's hashtags now resides. To access the site, Twitter users merely need to opt-in (for free) by following @hashtags on Twitter.

If you're writing a tweet about a topic you think might have a unique hashtag assigned to it, you can visit hashtags.org to find it.

When you arrive at the site, choose "Tags" on the right-side menu. After the menu drops down, choose "directory."

Hashtags are listed alphabetically, but the directory won't be helpful unless you have a lot of time. It's jammed with obscure-looking hashtags (many are acronyms). As a result, you might have better luck searching the site for your hashtag of choice.

Say, for instance, that you want to assign a tag to a new product that Google released. To find the official hashtag, type "Google" into Hashtag.org's search bar. It will return results with a list of Google-related hashtags.

The site also keeps analytics for popular tags, showing recent messages in which people used the tag, the people who tweeted it, and related tags.

How Hashtags Are Born

The Twitter community organically and collectively decides what a hashtag should be as it pertains to a certain topic. Third-party sites, such as tagalus and HashDictionary allow Twitter users to define hashtags. HashtagNation facilitates discussions around how certain hashtags should be defined and formed.

All of these user-generated sites have drawbacks. For one, they often fail to return definitions for common hashtags on Twitter. This could be due to the fact that some are really obvious — if you type #facebook into tagulus, for instance, no results appear, as no one bothered to take the time to note that it would be used for a tweet about the social network.

Secondly, because multiple dictionaries chronicle Twitter hashtags, definitions for the same hashtag can vary.

Use Twitter Search to Find Hashtags

As Twitter hashtags became more popular, Twitter integrated them into its search tool. You can search for a hashtag in two ways.

The first: If you perform an advanced search, under the "Words" section, you can search for a hashtag.

Or, you can simply use Twitter's main search bar (which they recently made available on people's home pages), and put a "#" symbol in front of your hashtag.

Whichever method you decide, Twitter will return back results with tweets where users employed the hashtag. The upside to an advanced search is that you can define dates, so you don't return hashtags since the beginning of Twitter time (unless, of course, that's what you want).

Use Hashtags Judiciously

Hashtags can be overused. Chris Messina, a San Francisco-bases social media consultant (who was credited as first formulating the hashtag idea in his blog), noted some of the drawbacks in a post about how to make the most of hashtags.

"Already it's been made clear to me that the use of hashtags can be annoying, adding more noise than value," Messina wrote. "Some people just don't like how they look. Others feel that they encumber a simple communication system that should do one thing and one thing well."

As a result, he said users should make use of hashtags sparingly and only when they bring additional context to a tweet that would otherwise be absent. For instance, take these examples:

"@google gave a nice presentation. #CIOconference."

That tweet, with the hashtag, would provide better context than:

"@google gave a nice presentation."

In this case, the writer of the tweet informs people that his message is meant within the context of a conference he is attending. The benefit: his followers do not need to read past tweets in his Twitter stream to find out where he is or what he means.

My Two Cents

Twitter's hashtagging system remains a nascent form of organizing the Twitter world. Messina's contention that they should be used sparingly is well-taken. Hashtags have largely been employed by Twitter's first adopters, and their overuse has two unfortunate consequences.

First, hashtags can give Twitter an insular feel that will detract people from staying on the service, as evidenced by Twitter's poor retention rate of new users (60 percent bail not long after joining, according to recent Nielsen research). Second, it's presumptuous (and ironic, considering Twitter power users' championing of social technologies) for these folks to assume they know the best way to organize the service before more average Joe Web-Users have their say.