I was serving on a grant proposal committee, and I watched as a fellow judge asked his Twitter followers if a certain project had been tried before. In 15 seconds, his followers replied with Web links to the information he needed. No e-mail message, phone call or Web site could have achieved the same effect.
Twitter, in other words, is precisely what you want it to be. It can be a business tool, a teenage time-killer, a research assistant, a news source — whatever. There are no rules, or at least none that apply equally well to everyone.