Nielson on Information Pollution

Have you ever been typing mid-sentence when a blasted IM window pops up and captures focus, essentially sending the last half of your sentence to a colleage or friend?

Nielson describes this as Information Pollution and I would have to agree with this assessment.

IM is even worse than e-mail with respect to one of the most important human-factors criteria: It's interruptive of task flow because it demands realtime attention. Some things do need realtime attention, but even a one-minute interruption can easily cost a knowledge worker 10 to 15 minutes of lost productivity due to the time needed to reestablish mental context and reenter the flow state.

Source: ACM Queue