If you need to reach someone at his or her office, the phone--we now know--is not the best way to do it. E-mail is easier and more popular, as evidenced by the deluge of messages with which cube dwellers are greeted each morning as they log onto their com

But what do you do if you have only a few quick words to say and need only a few back in return? You do what a growing number of office workers are now doing: access your instant messaging service. According to Insight Express, a Stamford, Conn.-based online market research company, 20 percent of those who use an IM service do so from the office. But far from i-chatting with pals (AOL, in fact, has two delineations of IM user: "co-worker" and "buddy"), office workers are using instant messaging to facilitate the completion of their workload. Overall, almost half of the respondents in the Insight study, which was conducted in July, said they use instant messaging, with the overwhelming majority (96 percent) of them using the service at home. As for IM services replacing the phone and e-mail, 49 percent of all respondents said they use their IM service in place of phone calls and 35 percent said they use it instead of sending e-mail