Twitter 101: An official how-to guide for the David Lettermans of the business world

Microblogging service Twitter is hot — or at least it has been experiencing heat waves of growth. So the company has just rolled out an extensive guide so businesses can get a better understanding of how to make use of its 140-character broadcasting service. Called Twitter 101, the guide includes a whole range of stuff: Simple explanations about its features, case studies from companies like Best Buy and Dell, best practices, and links to some related sites. All in all, the information seems pretty basic.

And yet, prominent brands — like David Letterman, host of the Late Show with David Letterman — still seem to be getting their heads around the service, so this guide comes at a great time. Twitter 101 is also not the only explanation-focused interface upgrade that the company has planned. The company is also planning a new homepage, to be launched next week, that will “a search box, information on Twitter trends and a panoply of more specific information about how they can use Twitter,” according to AllThingsD.

The service has been growing fast, sometimes by leaps, sometimes by bounds, but also sometimes by small hops — at least according to third party services, as it doesn’t release internal numbers. It is still trying to take flight. In June, comScore reported that it had 20.1 million US users, up 14 percent from May’s 17.6 million users. But in May, it grew only 3.5 percent, from 17 million in April. Meanwhile, various reports show that not all Twitter users are actively using the site; some are just reading tweets but not sending them, while others are signing up but not coming back. This may not be entirely bad news, as users could be taking months to get used to the service (see our previous coverage on that for more).

Twitter 101 makes no mention of how Twitter might make money. Many have expected the company to roll out premium services designed for businesses, although this could be coming later. Twitter 101 could just be setting the stage for revenue. Meanwhile, the answer to David Letterman’s naive question about the service the other night, posed to show guest Kevin Spacey (“Does that cost you money, to be on Twitter?“), is still a complete “no.”

The guide was announced by Twitter co-founder Biz Stone today at Fortune’s Brainstorm: Tech summit currently happening in Pasadena, Calif. Interviewer Adam Lashinsky asked him on-stage about the business model. His reply: “The plan is to do that this year– to show some signs of life for a revenue approach” — the “first step” is “Twitter 101.”