Another article, this one at Red Herring, on IM in the workplace:

A recent report by Pew Internet and American Life Project showed that 11 million people use an IM service at work, and 53 million have used it at home or in the office. But those numbers have yet to translate into a lucrative market. By the end of this year, IM conversations will generate $131 million in revenues. But by 2008, that figure is predicted to jump to $413 million, according to the Radicati Group, a technology market research company in Palo Alto, California.