The first reaction I had reading this was, "how many times do I chat while I'm on the phone, or read an e-mail while chatting, or even on the phone?". This is not always the most productive way of doing things, and it takes great discipline to focus on one thing. So let's change that, well not really.
This trend is trending upward, more people are doing multi-tasking, what does this mean for me? As the post author says - getting the attention of people is becoming more and more difficult. I consider this an important trend to take into account when designing a user experience, our design must take into account that people's attention is not fully there. Making an easy to use product, with low customer support to use common business goals - takes a different direction when one knows about that trend.