Among the three leading brands of instant messenger - America Online's AOL Instant Messenger (AIM), Microsoft's MSN Messenger and Yahoo's Yahoo Messenger - business use was up 110% in the US over the past year, from 2.3 billion minutes in September 2000, to 4.9 billion minutes in September 2001, according to the research firm.
Instant messaging has seen explosive growth in the workplace, with over 13.4 million unique users counted in September 2001.
"A lot of companies will expect most of their staff to have either AOL or MSN, so they can communicate with colleagues," said Jupiter analyst Dan Stevenson. "But equally, people are using them for communicating with friends, either in the office, or outside."
Many office users install more than one instant messenger to get around the fact that, so far, the leading services are not compatible, Stevenson said. Ironically, AOL's refusal to co-operate with its arch rival Microsoft is driving growth among competitors, he said.
"[AOL is] continuing to block competing messaging technology, so it's giving the initiative to users to download and use the other services."
Despite the rapid growth of instant messaging in the workplace, business users are still far outnumbered by home instant-messaging enthusiasts, according to the Jupiter research. Home users increased by 28%, from 42 million in September 2000 to 53.8 million in September 2001.
In the workplace, as at home, AIM is the leading instant-messaging brand, but its competitors are gaining ground, Jupiter reported. AOL counted 8.8 million unique business users in September 2001, while MSN had 4.8 million users and Yahoo had 3.4 million users.