I don't think blocking is the answer. I am running an in-class experiment next week that requires all of the students to bring their laptops/netbooks and connect via wi-fi to participate. They will get to see the results of their actions in real-time. I couldn't do this if we had to use a computer lab because we don't have a single lab large enough. I could have the students join in from other locations but then we could not discuss the results as they happened.

I think we have to be concerned about keeping students engaged. If we do that then they won't be constantly on their phones texting and what not. Sometimes, the gadgets can help us do that.