Twitter is getting ready to launch a search engine that would make it possible for users to search for keywords and phrases being used by the people they follow on the popular messaging site, the company said this week.

Twitter Search, which would be incorporated into each user's home page, is being tested by a select number of people who have had the feature for the last few weeks, Twitter co-founder Biz Stone said in the company's official blog.

"We are loving this implementation of Twitter Search and the technical infrastructure to support it is mostly in place," Stone said in the Wednesday post. "We'll gather a bit more feedback from our test group and then get these features out to everyone as soon as possible."

The other features include the ability to save a search keyword or phrase and have it as a link on the home page sidebar. Clicking on the item lists the results where the short messages, or "tweets," of the people a person is following are normally displayed. The same screen is used to display search results.

Tweets are the mini-messages people send over Twitter. The messages have a 140-character limit.

In addition, the sidebar has a trend section that lists words or phrases "being referenced with more frequency suggesting that something interesting might be happening," Stone said.

"When you click on the trend line, you can read the tweets and find out what's up," Stone said. "Trends is in beta -- but it has potential."

Twitter Search would be unique in that the results would have more immediacy then what's available on more traditional search engines, such as Google. Web content displayed on Google must first be posted by a blogger or Web site and then discovered by Google's search engine. In the case of Twitter, the information would be available as soon as someone starts sending messages, which means a person can find out what's being said about a particular topic while it's being said.

An example of how Twitter would be more immediate is what happened after the crash landing in January of US Airways Flight 1549 into the Hudson River in New York. Because of the skill of the pilot, all 155 people on board survived the crash.

Where traditional search engines wouldn't have information on the crash until it was posted on a news site or blog, Twitter had the information immediately from eyewitnesses sending messages and pictures through the network.

Twitter's potential in search hasn't been lost on Google, which leads the industry in number of Web searches and in search advertising. Google opened a Twitter account in February and uses it as a marketing tool for its services.

While the number of people using Twitter is in the millions, the company has yet to disclose a strategy for making money on the service, which is being tapped commercially by other businesses. Some have started brokering ads that run alongside tweets using the application programming interfaces Twitter makes available to developers.

In a recent interview, Stone said the company is getting ready to launch a paid premium service this year, while still offering its current free version.

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