[niuboshi]

Two points here. I don't have a Facebook account (probably never will), so I suspect the Facebook hits were mostly from Salon.

On the browsing Twitter stuff, I'm kind of fortunate. Since this hit here and on Boing Boing, I've been following along (and have been pleasantly surprised at how nice the internet is). But, I'm in academia, and this very tangentially counts as "work."

But yes, I also agree, people are doing this, and they'll continue to do so at work. As for how that fits with your model of a productive workplace, YMMV.