There are a lot of odd acronyms floating around Twitter. Apart from urban slang, and weird Web 2.0 website names (i.e. Squidoo, Kirtsy), there are “hashtags.”

A hashtag is a word or set of words with a “#” in front of it. This was originally designed so that when you are looking for a specific topic on the Twitter search engine ,  it was possible to find quickly. An example of this is the place name “San Diego”. If you look it up without a hashtag, you get everything with those keywords including source material (names of publications) showing up. With the # in front, #sandiego, you can get the exact subject you are looking for.

Of course, this assumes that everyone on Twitter remembers to use the hashtag. Many do not, and others make up their own hashtags as they are writing their tweets. So, in order to figure out what peeps are talking about, I recommend using the site What The Hashtag? .

This website gives you the trending hashtags, active tags, and a word cloud of tag categories. It is free to create an account, and they now have a set of tools that can help you figure out the odder tags.

There are also a lot of chatspeak acronyms that show up in Twitter. Many of these were originally used in chatrooms, and then in text messages  (SMS) on mobile phones.

I would also recommend the Twittonary as a place to look up Twitter words.

Twitter know lets you see what the trending topics are on your Twitter home page. However, many of us do not have a clue what these topics actually are.

What the Trend? to the rescue! This application (by Matt Mayer) explains what the topics are, when they started and the last time they were tweeted about. If you click on a trend, you can see the tweets, any news or photos (from Flickr) about the subject as well.

You can also follow @whatthetrend on Twitter.

Twitter does have search available since they bought the site Summarize. To access the Twitter Search, go here . The page allows you to search by topic, and has a list of the current trends at the bottom.

Someone figured out that if you put the # in front of a term, people could find it quickly here. Voila! The hashtag was born. (The term may have originated from somewhere else, I’ll look into that.)

So, when a number of people are at a conference, such as BlogWorld Expo, they try to agree on a single tag and then place it somewhere in their tweets, like this #BWE08. This allows others to find their comments under one search instead of having to do variations on the name of the conference.

Some people have gotten a tad crazy with hashtags (IMHO), tagging everything they think is useful for others. A number of people have put together online parties by using the hashtag so that others can see who is online without following them. Warren Whitlock put such a party together over New Year’s Eve by using the tag, #Happy09.