Twitter, without a doubt, has had a nice run as the hot topic in advertising and media circles. But what it means for businesses is still murky. Everyone points to Comcast and Zappos as examples of companies that use Twitter in the most effective way. Today, 360i rolled out a broader look at social media in the form of a 56-page “playbook,”complete with a checklist to decide on what, if any, Twitter strategy companies should use. Performics, the VivaKi search shop, pondered the best way to use Twitter in a recent white paper. Finally, business-to-business shop Doremus asked its site visitors for their feelings on Twitter as a business tool. The results were mixed: 40 percent said it was useful, and 40 percent said it wasn’t. What’s pretty clear is that both agencies and advertisers are figuring out their roles as they go along, with probably the best course of action being trial and error.