In its ongoing effort to figure out how to make money, Twitter has launched a new search tool and an online manual for businesses.

The idea is that businesses will learn to use Twitter to market themselves and possibly pay for services that Twitter could roll out later.

The widget can be programmed to follow Twitter's 140-character messages, called Tweets, on any specific topic -- a company name, product, or brand -- as they are posted to Twitter's site.

The manual, which was intermittently unavailable on Friday, features best practices -- "use a casual, friendly tone in your messages," "don't spam" -- and case studies on companies such as Pepsi, Dell, and JetBlue that have used Twitter.

Suggestions include using the micro-blogging service to offer coupons, shopping tips, and messages about "fun, quirky events at your HQ, giving others a small but valuable connection with the people in your company."

The roll-out was accompanied by a story in The New York Times claiming that small businesses are using Twitter, along with a report from the Wall Street Journal's All Things D blog that Twitter will launch a new home page next week that will be less confusing to use.

"We're focused on enhancing value across Twitter in general -- these documents are just a first step," wrote Twitter co-founder Biz Stone.

Twitter has had some challenges lately, in addition to occasional downtime. Internal documents about the company's financial projections and other matters were leaked last week by the blog TechCrunch, whose founder Michael Arrington said he got them from a hacker.

Twitter, which has raised $55 million, expects $4 million in revenue next quarter and $140 million by the end of next year, the documents said.

The service is also being used in some unique ways. For instance, the blog ReadWriteWeb reported Thursday that an engineer for Texas Instruments, Matt Morey, uses his Twitter account to control his lights and home appliances through a gateway from ioBridge.

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