Lecturer lost to the Facebook jungle

It’s 4.40pm on a Friday and every student is staring at me attentively. They are not peering at Facebook, they are not tweeting, and there’s complete silence in the classroom. I’d like to say this is because I’m such a great teacher but sadly there’s another reason – namely that for the first time in five years of casual teaching at universities I have lost my cool and screamed at one student to shut the frick up or get the frick out of my class.