In the March issue of Inc., I wrote a story about Twitter co-founder Evan Williams. The piece, which focuses on Williams's ideas about the accidental nature of company building and on the value of thinking small, brought me very close to Twitter, an odd (and oddly popular) service that allows you to blast short messages to your friends' cell phones.

Like blogging in the early days, most of the attention Twitter has received has focused on the social aspects of the phenomenally popular service. There's Twittervision, a voyeuristic mashup that shows what strangers are doing all over the world. There are Twitter journalists, like Time magazine columnist Ana Marie Cox. There are even Twitter cats.

But an aspect that has received less attention is what Twitter can do for marketers. For instance, Peter Kim, a Forrester analyst and loyal Twitter user, has written about Twitter as a way to monitor how your company is perceived. Here's how it works: Let's say you've got a big announcement coming up and you want to know how people react. You can set up Twitter so that it text messages you anytime a Twitter user (there are roughly a million of them) mentions your company, your brand, whatever. Because Twitter is instantaneous and personal—people generally only write for their friends—you tend to get snap judgments. (The site is filled with accounts of customer support calls, laptop crashes, and television commercials.) But what's really cool about watching Twitter is that you can watch perceptions change in real time.

Check it out by creating a Twitter account and then sending "track [your company name]" to Twitter. Or, if getting instantaneous feedback sounds too stressful, you can search Twitter posts, or "tweets," using this search engine.