IM Use at Work Here to Stay
I know that IM has been essential for me to do my job for 4 years. I was responsible for IM being pushed as part of a large Canadian telco. I had been working with a web development company and we used Yahoo’s IM client extensively. It then spread internally and when this company was acquired by the telco, the president of the acquired company fought for (and won) keeping Yahoo IM as part of their tool set. They had found it was a faster way to communicate amongst offices across Canada than phone or e-mail.
As far as I know, some of the folks there still use it today four years later.