Instant messaging has come of age. No longer the province of chatty teenagers, it is now an important part of advanced communications networks at many corporations. And as instant messaging takes hold, companies are benefiting from new productivity gains and improvements in customer response time.

　　 “I almost never get e-mail from my Sun colleagues,” said Tim Bray, an avid instant messager and director of Web technologies for Sun Microsystems. “And I only get voice mails from outsider.”

　　Sun isn’t the only technology company to embrace instant messaging. “We send 2.5 million I.M.’s within I.B.M. each day,” says David Marshak, senior product manager for collaboration at I.B.M. “And we have virtually zero voice mails here.”

　　Years ago, when PC’s were spreading through corporations, many companies eliminated secretaries on the theory that the machines would enable professionals to do their own typing and send their own messages by e-mail. But phishing attacks, viruses and spam have clogged e-mail networks, and voice-mail boxes are also overflowing.

　　Now a generation of office workers who grew up with instant messaging has gained control. They have made I.M. the latest trend in information technology. Along the way, they have change how the corporate world converses and have built a series of new communication applications.

　　Instant messaging is becoming an important ingredient for corporations that want to respond rapidly to demands from inside and outside. They are using it to tie customers closer together and to enable workers to communicate across the globe.

　　One example is IntelliCare Inc., based in Portland, Maine, which operates call centers for health care providers. Everyone in the company uses Lotus Sametime.

　　 “One of your nurses answers the phone when you call your doctor in the middle of the night, and 97 percent of our nurses work from home,” said Jeff Forbes, chief information officer. “The nurse can fire off an I.M. to an expert and get a response back without having to interrupt your call.”

　　Banks, insurance companies and other old-school businesses are using instant messaging to communicate with customers and quickly route queries, all within seconds. In the not-so-distant past, e-mail was considered state of the art, and responding within 24 hours was considered prompt. Those days seem quaint now; instant messaging is used in more than 80 percent of corporations, according to a report by Michael Osterman, an industry analyst.

　　Among the most important factors behind I.M.’s quick conquest of the business world is geography. Finding someone often requires more than just making a phone call or sending an e-mail message. With instant messaging, a correspondent knows who is available, and who is not, at any moment.

　　The group-chat mechanisms of I.M. also make it easier to have multiple conversations going, and one-to-many conversations.

　　Finally, e-mail is woefully inadequate for guaranteed delivery and clumsy when it comes to conducting business in real time.

　　Nevertheless, business use of instant messaging has some unresolved problems. There is the question of interoperability among the four largest I.M. vendors: America Online, Microsoft, eBay/Skype and Yahoo. Each is independent, and users of one cannot communicate easily with users on others.

　　Increasing numbers of major corporations are deploying their own large-scale internal instant-messaging networks, pushing I.M. further into the mainstream. The process is reminiscent of when corporate intranets were first built, in the mid-1990’s.   Which means the end could be near for business voice mail, as more and more companies adopt instant messaging.