Random job network My Job Group has done a 1,000 person survey that shows 55% of people polled access social media at work, with 6% doing so for more than an hour each day (I was not polled, but I expect I would be off th chart...).
Somehow the poll has calculated that social media is costing the UK economy billions in lost work time. Based on the fact that time spent reading / speaking / playing online has a negative effect on the rest of your day.
Even if people do waste more time at work now on the net than they used to on things like solitaire, emailing friends or talking to people, I disagree that the amount of time left to spend working is equal to total productivity.
I'm a strong believer in using focus, batching, channelling creativity, and Parkinson's law. If you ask me, even if your job can't be done better using the net in some way, you can definitely do better work when you are focusing by spending time not focusing, if you get what I mean.
So thanks My Job Group for the PR survey, but I don't think you've nailed the social media bit or the workplace productivity bit either.