I spend a lot of time at a keyboard and screen. Most of the time, I'm working. I might be writing code or a document, reading something to better myself, reading something because it's my job to review it, watching a video or screencast, triaging bugs in TFS, or of course processing email. Some of these tasks involve a lot of typing, others mainly mousing, and some involve sitting almost completely still with the occasional page-down or mouse click. Other times, I'm having conversations with family or friends, reading something for fun, or playing a game. These tasks also have the same spectrum of frantic-typing and clicking through to mostly passive consumption with the occasional click or keypress. And at still third times I'm doing what we might call family administrative tasks - seeing when the grocery store in a nearby town closes, checking the school web site for holiday dates, ordering something, renewing something, banking or billpaying - or business administrative tasks - including invoicing my clients. You can't tell, by looking at the back of my screen or listening to my typing and mousing, what I'm doing. You can't tell by where I'm sitting either ... I might be using Remote Desktop to access the computer where our book-keeping software is installed, or a server that needs to be configured, or a client machine so that I can reproduce a production problem.
So what? Well it isn't how work has usually been. Hundreds of years ago, if someone was working you could tell by looking at them. They had a hammer in their hand, or a paintbrush, or some other tool. Even a few decades ago, if someone worked at a desk by writing on paper it was easy to see what desk they were at, what papers were strewn around them. Reading the paper looked very different from checking the invoices. And of course, leisure never involved the same tools or locations as work. Now, not so much. Bill Buxton has an interesting article on just this topic. He's at Microsoft Research, and it pleases me to think that folks there are thinking about this. I look forward to a future time when people can get a better idea of what I'm doing and how interruptable I am, not just "you're always on your computer."