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.